Most of us were raised with family values to help our family and our friends when they needed it. We are really enablers helping them when they won't take care of their own affairs. We do have to step back and say "NO MORE!!!"
I was watching Joyce Meyer (female evangelist) today and she was talking about this very same issue.
http://www.joycemeyer.org The message for today on TV 5/18/06 was dynamite! I have to agree with her that sometimes we do it for approval so we won't be thought of as uncaring. (you can listen/watch to it on the website if you want to.)
Sometimes you have to walk away from a bad situation with family and friends for your own sanity. Pray for them and know that God in is control.