My Brother Has A Very Dry Irritating Cough Every Night.

My brother has a very dry irritating cough every night. He's complaint of some kind of obstruction in his throat. He's been on antibiotics for 2 weeks and his doc told him to cease all meds. He's lost so much weight, sweats profusely in the nights, day as well. He's lost energy and not himself. We changed his diet to vegan. Age 46.