There is no specific treatment for a viral fever
. Symptomatic is usually enough. Apart from Tylenol motrin
i shall give you few tips. Tepid sponging can be done. Sponge you son's whole body with a clean cloth soaked in water. If you are covering your son in a blanket, please don't do that. Fever is a process in which the heat is let out from your body. If you cover your son in a blanket the heat doesn't escape and fever is not controlled. You child is lethargic as fever is high metabolic state . Give him plenty of fluids. Fluids doesn't mean water. Body needs electrolytes along with water. The best Fluid yo can give your son is Fresh lime juice with little salt added. You can give him ORS
as well (Oral Re hydration Solution). Hope your son recovers soon.
Wish you and your son a healthy life
Take Care, Bye