I think most airline employees would be happy to do whatever is necessary to accommodate a deaf passenger. On a human level, most GAs and FAs seem more than willing to help someone with a special need. The problem is with the system. (The airline industry as a whole.) Seems like they see passengers with limitations as a minority or "special circumstance." I don't think the airlines are truly prepared to handle deaf or even disabled passengers. They most likely concentrate their planning and efforts on the majority of pax without special circumstances. These are just my thoughts and opinions. I don't claim to know what is like for deaf pax or airline employees who are there to help them.