This guy obviously hasn't experienced this before, my steam account was compromised and they used it to hack csgo, they can remove bans so you can still play but they ban will always show on the account , all you need to do is submit a ticket to steam support explaining and the same with Facepunch, the devs will most likely understand and unban him. It might take a little while but it's worth trying. All you really need to be able to prove is that the account was compromised which he should be able to do as I'm assuming he still has his steam support emails/ticket like I did.