I think the guy I like still likes his ex girlfriend....?!?

you're just going to have to be really patient. it usually take a while for people to get over someone they like. don't jump at the situation and automatically try to make him like you. take it slow and just be there for him. little by little, try to become the reason for him to forget his ex. try not to bring her up so much because it's only going to make him think more about her and less about you. :)