VAC bans are NOT issued for smurfing.

Game bans on the other hand. . . .

VAC bans are only issued for cheating not smurfing. So it sounds like a game ban, and no you cannot appeal it.

Also letting someone else play on your account is grounds for account termination. It will not work as an excuse to get unbanned.

Originally posted by knight's oath:

AI anti-cheat banned my friend for playing on his brother acc
So my friend got his ACC from his brother and got vac banned by the AI anti-cheat for "smurfing" even though he plays worse than his brother. Is it even possible to undo that VAC ban in this case?

first things first, not your profile not your problem, or are you making use of the "friend" excuse and it being you what got the account banned?

But anyway, if the ban is for smurfing then its a gameban and not a vacban, vacban is for cheating

vacban - https://steamhost.cn/help_steampowered_com/en/faqs/view/647C-5CC1-7EA9-3C29

Can I appeal my VAC ban?
No. VAC bans cannot be appealed.

I was not using my account when it was VAC banned. Can the ban be removed?
No. Any bans added to an account will remain regardless of who was using the account at the time the infraction occurred. Ultimately, the use and security of your Steam account are your responsibility.

While we understand this can be frustrating, we must maintain a zero tolerance policy for cheating to foster a fair game that all players will enjoy.

gameban cs2 - https://steamhost.cn/help_steampowered_com/en/faqs/view/4E54-0B96-D0A4-1557

Can I appeal my game ban?
No. Game bans cannot be appealed and are not removed from accounts.

I was not using my account when it was game banned. Can the ban be removed?
No. Regardless of who was using the account at the time the ban was issued, game bans are permanent and are not removed.

Your friend can't make his own thread? Why are you invested in his account?

The Steam discussions aren't the appropriate place to dispute specific bans, please read the following FAQ