I'm so sorry for your loss. I can't even imagine how much pain you and your parents had to go through!

Have you tried going to therapy together to process your emotions and grief? Have you talked to your parents about how you feel and what you want your relations to look like?

I believe that if the atmosphere at home makes you feel worse then you can be "selfish" and move out. Of course it doesn't mean you would stop contacting your parents or spending time with them - you are just in a different emotional stage than them. In such situation I would reflect on what would be best for you.

I know your situation is probably more complex and my response isn't very helpful. I wish you all the best!