For fungal infection
, after washing, dry thoroughly by pat drying, not rubbing. The damp skin is an ideal site for fungi to multiply. Also he should not share other people’s towels. Application of local antifungal cream (terbinafine, clotrimazole, econazole, ketoconazole, miconazole) and oral antifungal drugs are the mainstay of treatment. I would suggest a dermatologist’s evaluation for this.