Have a friend who is currently falling down the rabbit hole of a relapse after 3 months of being sober. We went to the OP program together. Any suggestions of how I can help him get back on track without being too pushy or annoying? I know he's going to feel like he failed and probably like it's not worth starting over. 
Remind him how good it felt to be clean. Reassure him that he’s not starting over. He’s picking up where he left off. Ask to go to a meeting with him if that’s safe and not too triggering for you.
If he is willing to go to a meeting, he has the willingness to get sober. Not 1 single person has ever gotten sober the first day they decided that they should. Recovery is not linear. UPS and downs and bumps and bruises happen. It’s the willingness to get up and keep moving that get us there.
Great suggestions, thank you Craig!
He has got to want it for himself. The one thing I’ve found is that I can’t talk anyone into wanting sobriety. I can only tell them how I did it, once they want it for themself.
I just came back from a 2 day relapse . It’s important to have boundaries right now. If he is serious about wanting to come back support him or let him know you are there whenever he is ready. This disease is so powerful. Took a split second to go from contented sobriety to guilt shame and remorse
How did this turn out?
Well, I haven't heard from him since this post, he fell off the face of the earth so I'm assuming he's still off the wagon 
Keep moving forward
That sucks, but don't take it personally. If we aren't ready, then we aren't ready, and nobody can change that.
Just keep encouraging this person and that nobody is perfect and we are all in this together that what makes recovery so great because we are together as one
Sometimes the best way I know to help someone is to remember what I was taught as a kid. We have 2 ears and 2 eyes. One mouth. It was a lesson on listen and watch what is going on more than you speak. Some issues will sort the right path is you just let someone talk it out.