He wasn’t born deaf but it happened at a young age. While his mother Naomi was out doing shows, she would bring Will along and her crew had to remind will to keep his headphones on all the time(since he is backstage near lot of amps). But having ADHD, he fidgets with the headphones and takes them off when a monster appears, leading to a amp being destroyed right next to Will’s ears causing damage.
This lead him to wearing hearing aids at a young age being only partially deaf until he discovered his sonic whistle witch made him go deaf. He knew how to sign before arriving at camp and after Leo was dropped off and Will gave him a tour, he learns morse code as-well because he understands what its like to want to communicate nonverbally.
And whenever Will is verbally fighting with anyone (mostly joke fights with Nico) he would just say “ive heard enough!” And turn off/take off his hearing aids for the rest of the day. He ofc takes it off when he is training or at the beach but most importantly when he is healing because he never knows when he overexerts himself. He also uses sign whenever he feels upset and teaches a class so other campers can learn asl! :}