(((JMF)))
I don't have any experience as the mom of an addict but I am a mom...and I can only imagine how hard it must be to enforce those boundaries sometimes.
What would you tell a good friend in this situation? Probably the exact same things that the wise souls above me have already said. I think its all about loving yourself. Putting up boundaries (like no more money) ISN'T about him...its about you and your wellbeing. Try not to look at it like your doing something TO him...look at it as doing something positive for yourself.
You're important, too, ya know.
Big hugs...