@Susan I agree. When I had my AirPods in all the time they started bothering me then I got an ear infection and haven’t worn them since.
He’s definitely listening too loudly. Maybe the bone conductor headphones would be better. Ear buds or over the ear headphones can be very damaging if listened for too long and too loud, multiple hours a day
They say you should only have your earbuds in a max of two hours each day and at the lowest setting possible -sometimes it’s anxiety/stress that causes the ears to ring. He needs to cut down on wearing the earbuds and see if it goes away.