Sounds like too much to handle, unless you want to. Everyone is free to make their own choices, and if you feel like dealing with a guy who has problems he wants you to deal with then do it. It's not the sensible thing to do, but I know tons of girls who get mixed up with guys like that and say, because they guy 'really loves' them somewhere in all the abuse.
It depends on ur strength. If u r able to handle it well then u carry on u might change them but if It is out of control n u r getting hurt emotionally or physically ..U need to let them go otherwise they r going to damage u