As you mention your husband having reccurent boils
on inner part of his buttock and groin i e recurrent staphyloccal infection not responding to antibiotics.
There are many causes of recurrent staph infection,but for your husband diabetis mallitus,any immunocompromise status,any chemotherepy ,or any immunological disorder are the main causes.
So test random an post prandial blood sugar ,test for any immunocompromise illness.
Also perfome culture sensitivity of of base of repture boil and according to that use proper antibiotic.
Daily sterile dressing of wound is also important.