Something similar happened to me Heart, a friend kept pushing me away and then being super nice and then really nasty and hurtful and then super nice again. It felt like a total head game and although I stuck it out as a friend to them, we gradually grew apart and now we dont really speak.. That aside I think just do your part, keep things civil and try to let what hes saying not get to you too much. Your friends will see that hes the one being awkward. Just stick it out and let go a little. Maybe if you have one other friend you can confide in you might feel a little less isolated?