Confusing, angry Ex, PLEASE help?!

I have some ex troubles. I was with said ex for 7months, and we were very happy together. we were best friends before we got together, which made things even better. I trusted this person with things id never told anyone about before, not stupid little things but very personal &painful things.I find it hard to trust people, and it was nice to have a friend. About 2months into the relationship he found out his father had cancer. He was devastated. He said that he was glad that I was there and I supported him, but I still felt it wasnt enough. 5months later when his father passed away, he called me to tell me, and I tried to console him but I knew there was nothing I could say to make it better. He broke up with me 4days later, with no explanation, just a text saying ‘I love you, but I cant do this anymore’. I was heartbroken, and it took me a while to get over it but I did. But since we broke up, my ex has gone from hating my guts to seeking my forgiveness&approval. A few weeks after we finished he tried to kiss me, and then ignored me a day later. He still calls me when hes down, but never when he’s happy.He goes through phases of texting me nonstop to ignoring me and giving me prankcalls with his friends. He tries to argue with me constantly, over stupid things.A few weeks ago he called me and asked me ‘have I ever felt suicidal’.2weeks ago he sent me over 100 blank IM messages.Even more recently, he got drunk and tried to kiss me, and then whispered ‘I shouldnt be doing this’. Then he started calling me a c*nt by text.Its annoying, confusing and it gets to me, because sfter all this, I still have feeling for him, and want to help him. I know this was long and boring lol but can someone help?