Fiancé toxic family

I need help. I have been in a relationship with my fiance for going on 4 years. We have a son together and are relatively happy. However, his family keeps causing trouble. They’re extremely toxic and are greatly affecting our relationship.

I just found out his mother has been telling him to hide money away from me. Saying I have money saved so why not put money away to spoil himself… meanwhile my savings have supported him during long periods of unemployment and when he hasn’t been able to pay bills.

On top of that she said my brother shouldn’t be allowed around my son because he’s a “loose Canon”. This is in reference to my brother calling the daycare to complain about mask manadates for a 2 year old. This resulted in my son being expelled. She said if the situations were reversed I wouldn’t allow my brother-in-law around. This stems from a past occurrence where the brother-in-law threatened to kill my child because he was mad at us… so, I have not allowed him around but he has reentered our lives.

She’s just extremely toxic and instead of doing anything, my fiance always yes her to death and just ignores it.

I dont know how much more I can deal with. I love him but I can’t deal with the toxicity anymore. There are so many other stories I could include but we don’t have enough time.

How much is too much?