I have 2 children, 1 ASD and 1 hearing impaired. BA have always given us free seat selection so we can stick together, a quick email after booking and it’s sorted. On boarding sometimes we have been approached and asked if any further assistance is needed, and other times not. My hearing impaired child was able to use her specialist headphones that plugged into her hearing aids, but I agree, on this day and age subtitles really should be an option on all films.