AHHHHH THIS IS ONE STRANGE GUY!!!! WHY is he doing this please explain!!!!!?

Hey, so I met this guy and we talked and he asked for my number. He also said that I’m very beautiful. We had some mutual friends prior to meeting. For an entire month he would invite me places and I would invite him places. We would often makeout too and when we hung out we usually were not sober either but we did not have nor did he ever try anything like that on me (even when we were alone in his room). at times we hung out sober too and all was good. After a month, he suddenly stops talking to me. Everytime I ask to chill he says: im super busy! Maybe some other time?...at the same time, he occasionally texts me when he’s drunk to chill or just random stuff but NEVER does it at the end. At the same time, when we are around eachother whether its drunk or sober he ignores me. He will say “hi” but act very coldly when he says it and then walks away. When he is with his friends (not mutual friends who live with him) they will nudge him and point to me and he would just stare. I’m trying to be nice to this guy cause we have mutual friends but he keeps giving me the cold shoulder. I talked to his housemate (who is one of my really good friends and who dosen't nudge him when he's around me) about it and his housemate told me that he is the type of guy who NEVER asks girls for numbers or barely talk to girls and that I was the first girl that he’s seen him with. Apparently, this guy always talks about doing stuff with girls but he has NEVER brought any girls home nor have his housemates (these housemates are people I knew very well prior to meeting him and they do not get along with him anymore) seen him with any…this is all very strange to me but what is going on? Why does he act like this in front of me? I know I shouldn’t care but b/c we have mutual friends I don’t want it to be akward or anything. At the same time, it dosen’t make sense because if this guy thought I was attractive he would have attempted to get to know me…if he was looking for a physical relationship he would attempt something when we were alone but he never did:s….can someone tell me why he is doing this??