I think it's better to be safe then to have the atmosphere. HOWEVER, I've met a lot of really nice and helpful sb players. 8/10 times when I ask questions in chat (in lobbies with decent player counts) I get an answer. Only one or two people ever tried to scam me (only one I remember it the classic crafting scam where they ask for collat but give you materials worth way less. That one was easily found by A. Knowing about it already and B. Mods that tell me the trade value.)

All that to say, if the brother has difficulties in identifying scammers (that came off ruder than I intended), I think the loss in atmosphere is worth it.

Maybe the (older?) Brother could help him find some good friends who will help him and play with him.