Am I wrong to feel the way I do?

Please post anonymous… My brother passed away from what was found to be a drug over dose. At first we were told it was a heart attack. His wife’s brother acted lik he knew nothing…it’s been 4 months now and now he’s came out that he got high with him that week and scored the sack that day. He came back and lied to my whole family that he knew nothing. I’m so upset. I want nothing to do with him. My sister in law backs her brother because that’s her baby brother… They were married 16 years and have 6 kids. Honestly to me I’m very stubborn and will cut people off… I don’t understand how she’s ok with him. And acts like we need to be ok with him too. My brother hadn’t gotten high in 10 years till the week before he died. He got some fentanyl laced meth. I can’t talk to anyone about this and I’m freaking out inside…