Do not give him any more chances, and don't even consider trying to make it work...it doesn't, it hasn't for a while and it won't.
He's not a good man.
It might not always feel like it, but you are better off without him.
Let him know that:
1) He has no right to confiscate your medication
2) His action in doibg so may actually be criminal.
3) If he doesn't give you back the medication, you can let the authorities know about his actions.