I'm with everyone else - I don't see any input from an ENT here, nor do I see any explanation as to why he has hearing loss. I would go to a pediatric ENT because I would want to know what caused the hearing loss. Once you know what caused it, you will have a better idea of whether or not it is permanent and if it is progressive. To me, these are the most important questions, because if you don't know what caused it, you can't keep it from happening again. And if the cause, whatever it is, is either ongoing or happens again (because you don't know about it and can't stop it), his hearing could continue to decline.
You want to know the cause and, even if the current hearing loss is permanent, you want to stabilize it so it doesn't get any worse.
Good luck.
(And, FWIW, I have mild hearing loss and function every day just fine. When I mention that a wear a hearing aid, people have no idea. Your son will be ok.)
ETA: As someone with mild hearing loss, I strongly disagree with those who say not to get hearing aids since you didn't notice the hearing loss. When a person doesn't hear well, they don't always do something obvious. In quiet houses and one-on-one situations, it's easy to follow conversations even if you don't catch every word because you can use other cues such as body language, facial expressions, and the situation to fill in the blanks. However, social situations in particular are difficult when you can only half-hear what others are saying, and it is exacerbated in groups of people where you can't look every person who is speaking in the eye while they talk (for a kid - in classrooms during group work, at recess, in gym class, on the soccer field).
Plus, your brain learns to adapt to a hearing aid - it has to learn to focus on important things while tuning out background noise, for example, focusing on voices and not the whistle of the air vent. We don't hear those non-important noises every day because our brain has learned to tune them out. When you first get a hearing aid, you brain has to learn to tune those things out in a different way. You don't just put in a hearing aid and suddenly hear perfectly, as if your hearing was never damaged. A person can't just wake up one morning and say - hey, I think I'll wear a hearing aid today - and have it work perfectly. It simply doesn't work that way.
Ok, off soap box.