Ur husband can try Tab Atarax
25 mg thrice daily after food for 5 days.It contains antihistamine which will reduce the allergic itching.
U can apply cutisoft gel 1% locally which contains Hydrocortisone
Along with the above two your husband can take T.Forcan 150 mg once daily after food for 7 days.Forcan contains antifungal agent fluconazole
These 3 medications should reduce the itching in your husbands buttocks and genital areas.