since high fever is life threatening it is strongly advised to consult medicine specialist and take prescribed paracetamol and antibiotics. after he is cured to avoid fever again take amla and giloy juice regularly. should do surya namasmar and Pranayam.
Drink plenty of water,eat soft foods like cooked cereal, mashed potatoes, soft fruits, yogurt and soft-cooked eggs...give adequate rest to your body..Avoid spicy foods or acidic foods.
Gargle with warm salt water. gargling several times a day can help relieve throat pain....he will require antibiotics to clear up infection..ask him to take dolo 650 thrice a day with tab augmentin 625 mg twice daily...if no improvements consult nearest ent surgeon they will do the needful.