PERSONAL BOUNDARIES have to be in place AND upheld before you can even begin to concern yourself with anyone else's boundaries.
It goes back to the airplane-put your OWN MASK ON FIRST-then you can help someone else.
FIRST you need to set down boundaries for what you will accept in a relationship-and stick to them.
THEN you can consider being a friend and helping him see the light of day (if he wants to).
"Love As Thou Wilt"