Is he busy, uninterested, shy or just want to be friends?

Long distance realtionship won't work out for so many people on a scale 1 to 10 in your case will be a 9 because he is studying medicine in America and your in Asia. Think about it how many years will he finihsed medicine school? It will at least take 7 years to finihsed medicine school. But it could be longer if you want to be a speicialist. Study medicine is not a easy program it need a lot times to study. I think he is tired of long distance relationship because when he want to touch or hug you he couldn't do it because your so far from him. So he feel bored and have pressue so he decide to talking to someone online instead of you. Becasue talking to somoene new he knows make him feel happy and interesting. He will forget the distance between you and him. He for sure just knowing some girls online or shcool that he might be interest at seeing everyday. He looks for you during the weekend doens't make he is in love with you. He just dont' want to hurt you now. So please dont' wait for him he will need a another few years to finished his study. He might arleady know someone by the tiem he finished his school.