Okay mom’s Im in a parent situation with my (4 yr old boy) cousins also boys but are 6,7,9. I had my sister’s baby shower here on Saturday. The first situation is that they purposely threw my kids balls over the fence. His mickey ball and his little sisters Minnie ball. Second my son’s grandpa (my dad) saw them all kicking and tossing around my sons plastic toy golf caddy (they broke the clubs the last time) third I saw a busted dump truck in the back area so I asked what happened and all the older kids said my son smashed it with his baseball bat (my son is 4 and NEVER has broken 1 toy) when I asked my son he said they did it. Later an adult came up to me and said she saw them all kicking and throwing and smashing it. All three of his cousins blamed him. How do I address this? This isn’t the first time they break his things on purpose or not. Oh and my mom caught one of them pounding on my son’s hot wheels track. Without coming off as something bad… Like I don’t want them to be defensive or take what I say the wrong way. I also over heard the grandma of his cousins say to my kid in the hallway “you better be nice Matthew” and his little cousin says “I’m good grandma” to which she replied “yes you are angel you’re perfect” my kid is hearing this and thinking he’s “bad” for simply walking back to his room …
We had a similar situation. When the cousins came over we put everything in the attic. Left out a few toys that my boys were willing to “share”. When they asked we told them we put them up. End of conversation.
First of all, those kids break my kids toys. I will make sure the parent go buy my kids toys as replacements. I will not let those kids back in my children’s bedrooms. The doors will be locked. The toys they broke will be in a box for them to play or go play outside.
They would never come to my house again.
Hell no, don’t be going around them anymore.
Have a conversation with the parents. If they don’t anything or you don’t have to confront the parents then put away all your sons toys when they come over.
They dont need to touch his things. Simply. If they can’t handle with care an respect
Don’t let them play with his toys. You can worry about their feelings, or your son’s.
I’d never let them back over. If my sister couldn’t control her kids then she wouldn’t be welcome either. Those kids are old enough to know what they’re doing and I wouldn’t stand for it.
Leave out a few toys that are sturdy and pack up all his favorite toys, put them away. The cousins can bring their own toys to share or play with what you put out. Because there will always be “accidents” …
Although it seems the cousins are just rough.
Only allowed them to play with his toys in the same room the adults are in. Good toys out of bounds and are not to be played with .
When my kids were little, I kept all the toys and parts together, my kids too care of their toys. When other kids came to play a basket of toys came out that was played with. My kids are 30 and 28 and I have given my grandchildren some of their parents toys. Being grown up, my son takes care of his vehicle, mower and such. It’s how you teach tgem
We have a closet that locks. Yes they did try to break in but couldn’t.
Situations like this is why there are “no children” invitations. It’s sad, because unless their parents witness their poor behavior and have the moral maturity to acknowledge it, then you’re going to have to find childcare and not have your son around his older, but obviously not mature enough, cousins.
Talk directly to those kids. Aren’t they your nephews? 
Let them know infront of their parents how you do not appreciate them breaking your kid’s toys and make them pay for it through chores etc. Being passive isn’t gonna change anything. They definitely will do it again.
I don’t care who you are, if you or you children can’t be respectful at my home you’re not welcome back. That’s supposed to be your safe space as well as your children. That sounds toxic not safe.
Sometimes if parents don’t step in & control their children you need to do it yourself. If the parents get offended then they can just not come back.
Stop being nice. These kids need to learn that it’s not their toy and they need to leave them in good shape. Or I would ask his parents to replace them
Support your child!! Right or wrong your child will remember your support.
Or especially don’t take your son around them. Seems they ALL are toxic af. CANCELLED!!! 
Stop trying to spare feelings. Call them out on this crap. You’re gonna make your kid think it’s ok for people to mess with his stuff in order not to cause waves. NO!
This is a sticky situation and very unfair to your son. If you absolutely have to have them in your home ask that they bring their own toys. Put the toys your son values away. If anyone says anything just explain that you financially can’t afford to replace broken toys. If they can’t teach their kids to respect others belongings then why should you feel like the ogre?
Have them start paying to replace the toys and don’t let them play
Simple they are not allowed over. Since they have been caught many times breaking toys and being disrespectful to property that Doesn’t belong to them.
Don’t allow them in your house
Reading about their behavior it makes me wonder what else they might be doing when no one is watching… They seem to be incredibly aggressive and violent. Besides the toys who knows if they aren’t going to go after your son at one point.
If you feel you HAVE to have them over at your house I would highly suggest to always be where they are. If they are in the yard, the adults should be there also. No free roaming inside your house. Lock the doors, and keep the keys on you.
I would definitely stop leaving them unsupervised. And let the parents know. And tell the Grandmom who I’m guessing isn’t if relation to you that she doesn’t need to assist you in any way in parenting.
Talk to your sister. And then the next time they come over make sure you put away his important toys. His favorites. So they stay safe. Then before they play, have a talk with all of them. Go over your house rules. If that were my kid, I’d be either replacing or having him go through his own stuff to give something to their cousin to replace what they broke. They’re young, but deff too old to be acting like that. More supervision too. Bedroom off limits, play where we can see you ect. If your sister can’t get on board with you and it continues and then I wouldn’t have play dates at the house anymore.
Your house your rules,tell the parents if they continue to allow their children to misbehave they aren’t allowed back,they get mad tuff
You mean your nieces and nephews? Really weird how you call them your kids cousins when it’s your sister’s kids. Those are your niece and nephew and its ok to correct them when it comes to your children’s things and being respectful. It’s the duty as an aunt to correct but I’d leave discipline to mom. But you can definitely say something to YOUR NIECES AND NEPHEWS not your sons cousins like they r only his
These boys sound like my youngest!! We have gone through everything and have almost nothing left from a new sectional every year along with new beds and bed frames every single year and never being able to keep anything for my kids to play with. 3 laptops 2 switches a ps4 1 tv and a million controllers later I still cannot figure out how to get him to stop destroying stuff
With that being said…. I always want to know as soon as possible what my child has done because if I don’t I can’t fix that problem just tell the mom what you saw and what happened she probably already knows her child is a little sh!t and already embarrassed.
The advice that has helped me. Have conversations and reminders about behaviors before walking them in the front door and let them know what this consequences are if those rules are not followed AND FOLLOW THROUGH especially if they are not your they need to know the boundaries you expect. And make sure you use a respectful friendly but stubborn voice so you don’t upset mom
Start making their parents pay for them. 
Seems like your kid and you are barely a priority in these family members eyes. As soon as the gma said that to my son after his cousins came into HIS space and wrecked HIS toys I’d be going to your sister and gma and saying hey y’all needa go. My child will not be treated like this nor will I. Y’all can teach them to be respectful then we will think about having them over. Advocate for your kid. Those boys lied on your kid about breaking his stuff so they clearly know what they’re doing is wrong. I wouldn’t allow them back over period.
Give their parents an invoice for replacing any toys broken
Dont let them come over tell they learn better