I'm not assuming anything, I am asking if it can be explained to me what the enjoyment would be. Why? Exactly for the reason you just said. I can see and hear and I know from that just how much WDW is built on the premise. There is nothing wrong with anyone going, and I have seen a lot of very disabled people, some that show no reaction to anything and the family is convinced that the person is having a good time. Even the tamest of attractions wouldn't be much more than a breeze on ones face without those two senses. I will put in that I don't know if that person said why he really wanted to go. If he indeed is finding something stimulating about it, then by all means he is a stronger man than I am.
If everyone remembers back a few years when people were taking along handicapped relatives and sometimes strangers to WDW to get to the front of lines and in large groups. One goes they all go. The question about if DAS was going to be a factor, just brought all that to mind. DAS now is just more or less a virtual queue but it still means that one will get to do something else and come back and not have the long line to contend with because they were operating on a no line situation. I'm not saying that is happening here, but since I have been fortunate enough to go with the ability to hear and see I really cannot picture how someone with problems involving both without having to have another sense take over to even have a chance of enjoyment. Just missing sight, yes someone can explain what it happening. Just missing hearing and one can see and therefore be part of it. With both missing, I frankly am at a loss.
I'm sure this will instill more anger toward me for having the tenacity to ask that question. I'm not saying this particular gentleman isn't finding pleasure in it, just some degree of reasoning so I can understand. It appears that this gentleman can speak so I'm wondering if he has said why or what he gets out of it. The bolded sentence in your post is the question, how are they communicating with him if he is deaf. They stated that he didn't know Braille and only has tunnel vision in one eye, if he can see enough to get the just of things than that explains it, if not then I just can't imagine what the joy would be.
By the way, I commend you for your time working with the deaf and blind. That must have been challenging and rewarding in the end. I know the four or five times I escorted mentally challenged and one of the finest people I ever knew that had Cerebral Palsy who could only talk with one or two words and could semi-walk if I held him up. That was before there was anything like DAS. It was a reward to see their reaction to the place, even that was a lot of work and if anyone thought it was easy, should try it once or twice. But, they could see and hear. Big difference.