pls help me what do i do ab him

ok first of all im gonna say he isnt diagnosed with autism (nothing wrong with thinking and telling people u might be on the spectrum but in this case it feels wrong)

ok so literally we were at a birthday party for my friend vinny. leo and vinny are bffs btw. so here we are all at dave n busters for vinnys birthday and i dont even know what happened but leo and nadia just wandered off so we didnt see them for most of the time. so its me, butler, sam, and vinny all playing games. we all had one card but for some reason leo and nadia had like 5 all to themselves, which seemed unfair because if any of us should have all those cards, it should be vinny. we meet at the prize thingy and for some reason leos all mad saying he gets all the tickets for all the cards and that its our problem if we dont have any tickets( none of us were saying stuff ab tickets). so im like nty and i walked away cuz im not getting sucked into his bad attitude. so leo and nadia r gone again. then we all meet up cuz we r ab to leave and leo is still acting like bitchy so leo starts getting mad at vinny cuz vinny asked why he was still mad. so leos like u know whats wrong.(he has a problem with sam for some reason). idk he was shouting and acting like vinny should have kicked sam out or something. and then we leave and act like nothing happened

alright this happened months ago but im still very mad about it(not the previous story). so leo used to have a crush on me and made it very obvious he wanted to date me even after i told him no. so i didnt know what to do and my other friend suggested that i should tell him that im already dating someone, so i told him that. well he still kept on texting me about his feelings when i told him i wasnt interested. apparently (AND I DIDNT KNOW) my friend told her friends about the situation and they went on twt and started shit saying how he cant just leave me alone and respect my boundaries. so i texted him and said that they were right and he just blew up on me and started swearing at me and saying horrible stuff, so i told him to stay away from me. a month or so went by and he said he missed me and stuff but i never got an apology, thats all i was waiting for was an apology. idk im still mad to this day.

alright so back to the birthday thing, we went to vinnys house and it was like, leo was demanding everything that happened. "oh i want cake" (vinny said he wanted to wait)   "we need to have cake now" and like what games we should play and he just kept telling everyone to shut the fuck up and butler finally snapped and was like whats with your bitchy attitude all night. leo was like im just returning the energy ur giving me (butler did not say anything to him at all)

ok next thing i know getting a proper diagnosis for autism can be hard and can prevent you from things in the future but like EVERYTHING he does he blames it on autism. when he says hurtful things, when he yells, like everything. like he wont own up to anything at all. and he says the r slur all the time and it just feels so wrong and i just cant stand being around him anymore. idk what to do. 

i want to tell him how i feel, but i know hes going to blow up on me