Is this Korean guy showing interest?

It's a question that you need to answer first. Do you want to be more than a friend? or would you rather stay as a friend? Having a friend is a great thing and I am sure you and he would both appreciate friendship. Maybe he values your friendship and have some comfort level that you two talks in casual level. Asking how you are or how you have done in exam are quiet common in Korean culture according to my korean friend. But, if you answered you want to be more than a friend or at least get to know him more, then look for signs that he has same interest in such matter then talk to him about it when time is right. Otherwise, enjoy a casual acquaintance, friendship and free study help he offers.