Very, very common. Some degree of hyperopia is basically normal at this age - depends on how much hyperopia, and the vision and symptoms as to whether child needs glasses. Sometimes the children need glasses and sometimes not. The main concern is to make sure he doesn't get amblyopia for a "lazy eye." I hope he is seeing an ophthalmologist. I can't make any comment on your son's situation. You can get a second opinion with a board-certified pediatric ophthalmologist if you have concerns.
MJK MD