And even if she's not...had Mr. Brando recognized his parenting limitations and not fought for custody of his children, BOTH Shawnee and Christian may have led much happier lives, suffered much less 'tragic' circumstances, and very well might still be around today.

From what I understand, Christian's mother was pretty unstable herself, so I don't know if he would have been better off with her either. I don't think the poor kid stood a chance given the family he came from.