My boyfriend the perk addict. Me the enabler.

My boyfriend had been snorting perks 30's before I started dating him. But he claimed to have stopped right when we got together. It's been two and a half years now, but about 8 months into our relationship I caught him twice in two days with a perk 30. The first one he claimed was a friends he picked up for. The second he admitted to. I brushed it off and threatened that he better not do it again. Now he would every great while claim that he was doing them for recreational purposes, but I wasn't dumb. But again, brushed it off. I thought he could just really be telling the truth, or I tried to convince myself of that. I recently found out that about 6 months ago he had been buying perks behind my back. Even when asked, he'd continue to lie. Even when confronted with it last week he said "Oh I only did it like 3 times more than the times I told you I did them for fun." Now I was frustrated. How was I supposed to know that 6 more months from now I wasn't going to find out he was still doing them now? Well I didn't have to wait that long. I was out with my mother and we made a quick stop back at his house so I could grab something and I walked in on him blowing another perk. He was a deer in headlights. I packed up all that I could carry right there. He was begging me to stay and telling me that he has a problem and needed help. I told him that I had always tried to help him and that he always said he was fine and didn't need help. I left with us agreeing that I will stay with my mother until he receives treatment. His mother is going to help him through this process, because I can't stay by his side, because then he won't seek help. My question is... How can I help him when I'm not with him? What can I do for him? Because I don't want this to be the end. I don't want it over.