What does it mean when a guy changes his mind about hooking up with you?

this guy asked me to the movies but things happened and i got horny so sex came up...Me and him were suppose to hook up and he was really into it and he stopped me in the hallway and even started asking me where we were gonna do it and all but the night before i texted him and he said his dad was too sick i didnt believe this so i just said ok i hope he feels better, so recently he texted me and asked can he come over my house to make up for the last time and i asked him what he was talking about and he said i dnt know if u dnt and i asked him if he was talking bout sex but he just said he wanted to hang out so why does he nt wanna sleep wit me now idc im just curious.