Minecraft Realms booting one of my friends

So, I have a Minecraft Realms and everything about it runs fine. The only issue is that for some reason one of my friends constantly is getting booted randomly from it. It's only him and sometimes we can play for 15 minutes and nothing happens. Everything is fine and then he gets kicked. Other times he can only stay on the server for a few seconds before getting the boot. All of us play through the Technic Launcher so I don't know if that somehow would cause an issue.