Suggest Treatment For Loss Of Hearing In A Child

my son has ear problem. his hearing in left ear is only 40%. at the age of 8 we realized that he was not able to hear with left ear and when we got it checked, Doctors said that his left ear nerves got effected and nothing can be done. but right ear they operated and removed the gum and anderoids blocking the ear and now it is fine. they are unable to say what age it happened and when and they said only remedy is that keep him away from cold items and he shold not effected by cold. can you please suggest any medicine available for left ear except hearing aids...