My friend gets 100-200 ping when on my dedicated server

So this is what happens, my friend joins my server and he gets 100-200 ping. But when he is on other servers he does not have that problem. He has been complaining to me about this for a while. Please help!

where does he live? if he lives in Europe or some place like that, he’s probably not going to get a much better ping.

He is in Indiana and I am in Pennsylvania.