Help for Athlete's Foot?

Can you please tell me what would be good for my grandson? He is 13. He has reoccurrence of athlete's foot.

Athlete's foot, known medically as tinea pedis, is a fungal infection of the foot that is spread easily in public shower rooms. Infection is more likely in a lowered immune system. The immune system is especially susceptible to fungal infections after taking antibiotics. Reinfection is common when the fungal spores remain in the shoes or socks. Synthetic materials in socks and shoes discourage circulation. The feet then remain moist, providing an environment for fungal growth.
To avoid infection, keep the immune system strong with a diet high in fresh fruit and vegetables. Eating natural, unsweetened yogurt provides acidophilus, the intestinal bacteria required to fight fungal infections. Garlic is strongly antifungal. Supplements can help to build the immune system to fight a fungal infection: vitamins A, C and B complex, with zinc, garlic and acidophilus.
Tea tree essential oil is anti-fungal, and provides an easy way to keep the feet free of fungus: wash the feet morning and evening in a basin of water to which a few drops of tea tree essential oil has been added.