GTI- Sulphur smell from exhaust

[Dzl_Dubba]

Hey guys

My Bro's GTI has sulphur smell (rotten eggs) coming from the exhaust when he goes to park the car after work. Is this normal? I know that the sulphur will oxidise when going through the cat but never smelt it from any other cars. Could the cat be the problem, or maybe even O2 sensor? He uses BP Ultimate btw.

Thanks