Are we talking about the account "yaboidobby" because he has 100% never sold gold to a site or anyone for that matter. His friends account i can't vouch for however, if he's sold gold then i can believe that.
Is it possible that lending gear/giving money to him as friend, has linked him enough in your eyes to his friends potential RWT activity.
Enough to warrant a ban?
How much gp are you saying he's supplied to gold sites? He's just never had that kind of GP.
What warrants a permanent ban vs a temporary ban?
Would appreciate if you looked further into this, get that you probably think i'm lying, but rn im laughing at the idea of My BIL selling gold, because in reality he's a bit of noob thats never had a large amount of wealth in this game that wasn't loaned to him temporarily.
Edit: Just to add: This is such an unexpected reply, because we assumed he was banned for buying?? the only recent activity on his account was him receiving money from his...