My brother has suffered from very severe itching all over his body for about 8 years now. he itches right after bathing or when he sweats. ?

See a dermatologist: There are various possible causes. You need a dr with special knowledge to get it right.

Cholinergic ?: If he has itchy bumps also, then it is called cholinergic urticaria which flares up after the body gets heated up then cools off. This can often be prevented by taking an antihistamine such as zyrtec (cetirizine). It may go away by itself with time but is not a serious health issue.