I think with the COL rise and more people cooking at home, there's plenty of people who would buy that. Especially apartment dwellers. Heck even I have a bbq on my balcony that I haven't used because of the fluff around with charcoal and gas and shit. So I reckon there is definitely a market for it.

Also agree with Seagoon, that selling it wholesale to a retailer is a good idea because your mate can then spread the risks around rather than taking it all on themself

Edit: actually, having thought on it some more, I think it would be way better to start local. Forget retailers. He can buy bags of charcoal, package it himself, and sell at markets and to people he knows; it's low risk already. Establish a solid, local base. People want to support small businesses and are generally moving away from the ColesWorth anyway. He has a solid idea, methinks.