Have you spoken with him about what he'd like? I think everyone has different tastes (both personal and also in relation to the types of hearing loss they have) and one of my buttons in particular is when people go out of their way to do everything... except ask what I prefer. For example, if he prefers to do video chats (I myself do), he may appreciate hand raising/visual cues before speaking (to context switch), cl…
Would set up a casual meeting with him to go over what he'd prefer, see what works best for the two of you and the company, and go from there. A big part of dignity is feeling like you have some choice in the matter, to echo OP.