Tellingly he laughed at the 'misconception' other hearing students had when he spoke in a lift. Far better he understood WHY, his hearing peers assumed he didn't, instead he mocked them? I don't think he is aware of how he is presenting to them if you spend 90% of your time signing and then start talking why wouldn't they be confused about that? Perhaps he can explain why he doesn't use his voice when he can? I don't think he can teach hearing anything but UNawareness. Either you can speak or you can't, you should be using whatever is necessary to communicate.
Or even:- No sign or text at all from the UK's premier deaf and HoH charity ?
Action On Hearing Loss Campaign from Angharad Stone on Vimeo.
It seems when it comes to awareness of deaf people, deafness or hearing loss, they haven't a clue.