Quite engimatic.
What seems clear, at least, is that his oppinion of you changed. The question is why.
The first reason I thought of was because he found out something he didn't know before:
Maybe he percieved you as a sweet girl with a common interest at first and was nice to you and might hope for it to get somewhere, and then found some sides he didn't like or that you lacked something. The difference in age could have contributed to this; you are after all in different stages of life. Maybe you are not old enough for him. So he regret his generousity and tries to end the friendship.
The other reason I thought of is that you misinterpretated his intentions:
He could just have been trying to be helpfull to a fellow Japanese student, in a professional way. Happy that there are people with interest he handed you some old test he had had use of and an anime he didn't need. Maybe he wasn't looking for a personal relationship and when you acted as it was he changed his attitude to show this.
These are the two ideas I can come up with, these are the reasons I could have acted like this (though I am too whimpy to be so rude).
I hope I have been, and will be, of use to you.
Many men are a bit introverted and maybe you overloaded him, another posibility. The only problem is that this would contradict the fact that he was very outwards earlier.
He wants a more badass girl? Well, it is possible, though it would be a risky tactic.