Is he really my friend? Or does his ADHD make it seem like he's not?

About 3 years ago at college, I met a guy and we became best friends. I noticed his behavior was a little strange but I didn't really mind, as he was nice to me. He fell in love with me and he used to be really sweet so with time, I fell in love with him too. We confessed these feelings for each other and all was going well until a friend of his transferred over to the college and he started ignoring more and becoming more distant although he still spoke to me at times and he still had that sweet personality. But him ignoring me caused me to pull away from him little by little because I felt like he no longer had interest in me. And one day he said something that really hurt my feelings and he didn't even apologize for it so I decide to completely shut away from him. After a few months of not talking to him or seeing him he emailed me to tell me he missed me. So I started talking to him again but not everyday like we used to, only through email. And he told me he had ADHD and also had a learning disability. At the time I didn't really understand much about those things, but still hurt by his behavior the previous months, I decided to be just friends with him and nothing more. We kept talking and we saw each other at college but not as much as we used to when we first met. This was a year ago. We graduated college this year and at the graduation he told me that he loved me still and he missed me and I love him as well so I decided to give it another shot. I started talking to him everyday again as we used to but I noticed his behavior change again. Over the summer he started ignoring my text messages. When he answered, his replies were more like one word answers. I asked him what was going on,and asked him why he was behaving this way because he had told me he loved me. He told me he saw my texts but forgot to respond and told me that he only loved me as a friend and that he should have told me. He told me he was going away on vacation and he would appreciate me not texting him as he wouldn't have time to text me back and that he wouldn't consider being in a relationship with me but would rather be my friend. And of course, I felt hurt again. He led me on again to then let me down. A month later there was a project he needed help with. I decided to help him and again he told me he missed me and started telling me things to hint that he liked me, just like when we first met. He started initiating texts again. When he was done with the project he started ignoring me again. And when I tried communicating with him he called me annoying and to stop acting like his girlfriend. He also told me he wants to find a girlfriend, that's not me.  I was just trying to be friendly with him, I wasn't even flirting with him. He says these things out of the blue. I have never done anything to hurt him and I've only been nice to him, so I don't understand why he would hurt my feelings like that. Imagine the person you truly love saying that to you. It hurts.  Since then, he has never initiated a single conversation with me. I talk to him everyday to check up on him because he feels depressed. I also miss him a lot and I feel very very hurt by his actions. He tells me he doesn't have time to really text me and he forgets because he's with "his other friends or family". I feel like he doesn't even consider me his friend when he says that. I'm very much in love with him. I truly care about him and sometimes I feel like it's all my fault because I should have dealt with his adhd behavior sooner and just try to work things out instead of not talking to him for all those months. I've been doing a lot of research on adhd in hopes that he'll be interested in me again because maybe there's something I'm not understanding and even if we can't be together, I want to be a good friend to him and be there for him as a friend should. As I said, I love him so much.  And I try not to tell him how I feel when he does these things because he'll feel criticized. I also encourage him to do the things he likes and I'm there for him when he's down even though he's not there for me. I know I can't force him to love him but I thought it was worth a shot if I started to learn about adhd. I sent him an email after all this about how much his friendship means to be. But he doesn't respond to anything nice I say to him. Is he just not interested in me at all, even as his friend? Or is he behaving this way because of his adhd and learning disability? I really need to know because I don't know what to do anymore and I feel so hurt. He seems to talk to me more whenever I encourage him and whenever he gives me the "silent treatment" he tells me it's because he's depressed, but I'm not sure. I want to believe him. Which is why I'm asking here. He used to be more attentive when we first met and now it's just me being there for him 100%. It seems like he has mood swings too. He does have long conversations with me sometimes and we joke around. But if I stop texting him for like a week or 2, he won't initiate the conversation not even to ask how I'm doing. Is his behavior like this because of his adhd and learning disability? If it's not, as much as it hurts and as difficult as it will be, I feel like I'll have to let him go.