i shampoo my hair every day <no conditioner> and my brother told me that you should only wash your hair 2-3 times a week as it dries out your scalp and accelerates hair loss. Now my theory is if that was true then the hair on my arms and legs would get thinner as well after daily applications of soap. The thickness of the hair in those areas has remained unchanged for many many years. I also assume that bar soap is far more harsh than shampoo so if there WAS an effect it would be MORE prevelent on arms legs etc.
PS if soap DOES thin your hair could SOMEONE PLEASE wash my back???
Definitiely no. Your brother is FOS.
Flaky scalp (dandruff or seborrheic dermatitis) is due to overgrowth of(and the inflammatory response to) a commensal fungus. The way to control it is DAILY shampooing with either a selenium sulfide shampoo (selsun), a ketoconazole containing shampoo (nizoral), or a coal tar shampoo. Make sure you leave it in for at least five minutes for full effect.
As for balding, if yer gonna lose your shit, it’s gonna happen. Minoxidol will temporize, but mentally prepare yourself to be the bald guy. Maybe some miracle cure will come along, but until then, wash daily if your scalp is flaky.