I don't know what to do with ADHD ex-boyfriend(?) anymore

I just want to say that I'm glad I found this website as I found the posts and articles here are quite helpful,

I really would like some advice to understand my situation better, as I am very confused at this point because I do not know what is the right thing to do.

I met Bill about 6 months ago in my place of employment (we're both 23), we do not work in the same sections but I have to pass by where he works to sign in; to make the story short a co-worker got us together and it was a struggle because apparently Bill has trouble approaching girls and it took him weeks to summon up the courage to text me. Bill was great in every way, except I noticed that he absolutely hates texting, smokes pot, one of the most reckless drivers I've ever met and if I don't specifically tell him what I want to do, he just drives me to his place to play games or watch something or he takes me to his friends house to play video games or watch something. Fast forward to 2 and a half months into the relationship, we have a big argument, mainly about him smoking pot. And he just tells me that he's addicted to it at the end of it he freaks out and breaks it off, he says that he doesn't want to hurt me with his recklessness, that he's a terrible person, that he still wants to see me and hangout with me and that we will work out in the future when he's better. We don't speak for two weeks, then we talk and he tells me that he still has feelings for me and wants to be with me but doesn't want to hurt me, so we hangout a couple of times after that (mainly initiated by me). After that, I'm not sure what it is, but he is always scared to approach me, he has to go to my co-worker and ask her about me or tell her to tell me that he misses me and if I don't give him the reassurance that I do want to see him, he won't make a move.

Now lastly, two months ago, he took me out and then he introduced me to his friends  then he asked me to go to a party the weekend after and everything was fine (all his ideas) and I thought things were progressing, because he was telling me that he is trying to change for the better and was opening up to me more. But then on a Friday he seemed a bit distant but then I went home and I texted him I missed him and he said that he missed me too and that we should do something fun this weekend I replied with "what were you thinking?" and he never answered... I confronted him at work as to why he never replied and he kept frantically apologizing. Now I took that very personally, it's not the first time he hasn't replied to a text, he has done it when were dating but this one really hurt. I avoided him for two weeks after that because I didn't know what to do. 

The last time I spoke to him was on Friday, I was working on something and he came up to me and just started talking about random things and every time I wanted to leave he would try and keep the conversation going. According to my co-worker he knows I'm mad at him and doesn't know what to do. I know for a fact that if I don't contact him, he won't do it himself because he'll just assume that I do not want to talk to him anymore, he gives himself such a hard time when he screws up. I want to msg him and ask him to see me and talk about it, I do not mind understanding him better if he is willing to work on this relationship but at the same time I'm afraid his behavior has nothing to do with ADHD and he just doesn't want me.

Any advice would be helpful!