I am hoping it has cleared by now , it sounds as if he has had a stomach bug of some kind with the fever, he would need hydrating, plenty of water then slowly add back food , rice Banana, what had he been eating prior to him having the diarrhea ,could also be an allergy but that possibly wouldnt accountfor the fever . let us know how he is , and if hes still unwell back to the Doctor with him or another Doctor .