He used to be my friend until he started spamming me and threatening to swat me. And he "forked" it which basically means he just copied the entire thing and posted it.
cant you just put a watermark on your game? and wouldn't blocking him solve this issue? I'm pretty sure if he lost contact with you after a while he'll lose interest.
website? as in .com? or do you mean a webpage from a game hosting site? if so you can still block him, and if it's your own site (even better) you can IP block him. also how can he pretend to be you?