Stasia,
Sorry for your loss. I hope you find the strength to deal with it in your own way. 🙁

About your SIL, I have been in a similar situation, not entirely the same. I know I dealt with it for a long time. It was always some reason.. She is mean coz she is clinically depressed, she is mean coz she is suffering in a bad relationship. She was loud, rude ad insulting for many many years which in turn caused a lot of problems in my relationship. It still is an issue.

But, I had had it with her. Talking in person with a person as rash as your SIL if useless in my opinion. I think she will barely listen to what you will say and I am worried she might just break your heart again with her rude words and behavior. What I did was write an email. An email that says it ALL, no holding back. And also, say it as is. No being polite and politically correct. Mine still did not get it and keeps making it sound like it is all my fault, but I know that she knows what she has done is wrong and that email will always be a good reminder to her. She has realized that she cannot get away with bad behavior and has started being civil, which I will take. I don’t care about building a good relationship with her anyways.

hope this helps.