Son voice gets hoarse on and off for about a year ent not concerned cause it doesn't stay hoarse and did no test. said from over use is this right ?

Most likely : In kids the most likely reason why the voice is abnormal is "overuse" or "improper use". The voice is best when powered by abdominal breathing and relaxation in the neck. All too often kids tense their necks when they speak causing tension in the voice box and leading to hoarseness. A speech therapist could be helpful in determining if that is your sons cause.