Is he newly blind or has he been blind for a long time?

I ask because I do some adaptive versions of old hobbies, like making hemp jewelry since it only takes tying knots essentially, and using clay or legos to build some stuff, rather than just doing it on the computer.

I also play tabletop games, but admittedly that requires a lot of focus and a fairly good grip on technology if you play online.

Depending on how bad his dementia is, you really simple tasks. I know that a long term care facility I was helping before had people stringing beads onto string and such, or someone filling out paperwork (in large print. I asked, and it turned out the gentleman was an accountant for decades, and liked filling in forms. Each part was a straightforward short question).

Try to find out what he liked to do when he was younger. You want to try to utilize him muscle memory if possible, so he can do things he is already familiar with. Knitting is good (if not complicated), but that assumed he knows how to knit originally.

Yes, I'd have to agree. I'm sure the dementia is the real problem. Would something like yoga or meditation work? Maybe some simple exercise would get the brain moving again, then you could try other things? I'm not sure how to get focus to work again though, but if you could make a start on something, it may help.

I'm assuming this is an older gentleman we're talking about, so possibly technology may not be one of his interests, but have you considered audiobooks? Granted, if he gets bored with just listening to music he still might get bored with that, but it's a thought.

Honestly, it sounds like his dementia-like symptoms may be more of a problem than his blindness is. Have you considered looking at it from that angle?