Parents: l'm worried about my sibling, advice needed!?

Maybe you could get social services too help your sister and when people mention them people tend too think they are there to take her child away its so not the case, They can provide her with help and maybe parenting cles too help her with the looking after of her child, and if he isn't helping maybe you could just talk too him about your feelings there isn't any need too cause a big stir as long as your sister is happy with him, and just be there for her as i am sure you are