Do video games cause violence?

My son has been staying up till 3am playing fortnight normally I would let him stay up because he doesn’t have to go to school for another week but once it gets to 5 days left boom that’s it he’s not allowed to stay up past 10 o’clock but I digress so my problem is he’s playing this game called fortnight and I have read on the media that video game is causing violence I know people say it’s wrong but my child has been shown to do weird things that aren’t really like him for example instead of feeling bad for someone when they fell over on TV like he normally did he was laughing at them I don’t know if it’s just puberty or actual fortnight in a previous post I have mentioned that he does think that the Earth is flat I don’t know if it’s a joke or not I haven’t really confronted him about it but is this behaviour just puberty or his video are games changing his personality and he knows thing about guns and he could name setting guns like asultrifle shotgun SMG and he knows what a silencer is