My husband and I met at university. We had some friends in common, and slowly started hanging out more and more until it was plainly obvious that we were mutually interested. This was my first relationship and I was a bit of a basket case stressing out about the whole thing for about a year, wondering if we should break up and such. But I was a little crazy that way. About a year into the relationship, I realized that we had gone through a lot of stuff together and nothing had broken us up yet, and that this is the kind of relationship where we will work hard and figure things out together, and that's the kind of relationship I want to have in a marriage. So from then on it was just a matter of time until we got engaged (yet another year later) and married (7 month engagement).
I can honestly say I have had zero doubts about marrying him since before we got engaged. This is strange for me, because I like to worry about everything, but I like to see this certainty as a true blessing from God, because I don't think I could cope with my anxiety and worry if I doubted our marriage.
As for your situation: It sounds like he's really not relationship material at this point in his life. I would certainly steer clear of getting romantically involved until he pulls himself together somewhat. Evangelism dating (even if it's just a "cut back on partying" kind of evangelism
) is always a bad idea. However, it sounds like you really enjoy your friendship, so feel free to keep that up, and wait and see if he's ever in a place in his life where he's relationship material. I wouldn't wait around for him, though, because he may never be the right guy for you. Just pray and trust God that he has a plan for your life, and then use your best judgement to proceed.