Good for you. Sounds like progress and change is afoot. I hope it all goes the best it can for all involved.
Just some food for thought:
and what will you do if he does not agree to go?
what will you do *if* he gets involuntarily committed...and gets out 3 days later?
If he agrees to go to rehab, where will he go/how will it be paid for?
I think I remember your wedding was scheduled for April, how will you go about letting guests know it is canceled?