Why is he in love with her?

Ok the way I see it is that he just thinks you two are best friends nothing differently he doesnt see you two a bf and gf. Or heres my other point of view hes is in love with you ad trying to make you jealous with you are being. Maybe you should go up ad talk to him about the situtation see what he likes about her etc. But dnt stop trying he'll love you someday.