Long time lurker, first time poster. OH is registered severely sight impaired (everything is out of focus save a tiny area on one eye), he is also deaf, as am I and this is noted on BA and on VS. Check in staff are very good, immediately ask if we need help. Security at LHR and LGW are brilliant, OH is always escorted through and then helped to find me - think about it, he can't see where I am. Don't get me started on security at JFK, EWR, TPA, etc., they are dreadful. OH is always detained, I am waved through but not allowed back to him, he is then abandoned and can't find me, it\s a nightmare. On board the crew are always helpful and attentive. Safety announcements are not a problem, he can't see the video or the crew demos but we've flown many many times so that's no problem.
OH can't see the films but has his iPad with large font and a very powerful magnifying glass with which he can read the headlines on the Times app and he has audio books. I tend not to bother with the films because my hearing aid causes problems with headphones (discomfort at best, distortion of sound otherwise) but am quite happy with the Times on my iPad and books on my Kindle. I suppose a sub-titled film would be possible, I've just never bothered.
What is a real problem is crew announcements. I know you have to read the same guff day after day and so, quite understandably, you recite it very quickly but deaf people miss most if not all the content. Doesn't matter whether it's BA, VS or (last month) Aegean, neither of us has heard much if any content of crew or captain announcements for years.