Deaf people often don’t speak because they are not exposed to voices; it doesn’t mean mute. Mute means they can hear but can’t speak.
But even if he were, there is an entire thriving society of deaf people who are bright, talented, and successful, and plenty of people who are partially deaf, including athletes, actors, and more.
May these horrible excuses for parents, who intentionally killed their child in a cruel and awful way, burn.