I concur with everyone else but I also want to extend sympathies to you and your husband on the death of his brother and brother's wife. It must be a confusing and tragic time for the whole family. I hope those children do find someone to care from them, losing both parents as a child must be terribly traumatic.

I think you are extremly kind and generous to offer to provide for them in education and other ways that you can. It's perfectly reasonable that you don't feel able to be a parent, you're no more able to be a parent than I am. That's not a bad trait, that's a good trait of self-awareness. I'm sure you are empathetic and sympathetic to the situation of the children, but they are not your responsibilty.

Keep a hard line here. Your boundaries are whaat make or break you. Best of luck.