I agree with @celia16 on the ideas she mentioned. It might help to think of your/his day like they do in early learning centers. Each block of time has a focus. Then when he says, what should I do, you can direct him to go to the “center” activity. Even if he just sits and ruminates during that time.
Things like:
It’s house work time!
Folding laundry (he may not notice that he folded all those same towels, or the stack of washcloths, or pillowcases, two days ago) Keep a laundry basket with stuff ready. Or, Empty the dishwasher (onto the counter?) Or, Dry mop the floor.
It’s outdoor time!
Clean your tools, wipe them down. Maybe there are lots of tools? Maybe he re-cleans them. Or, Sweep the walkway. Or, sit in the shade/sun. Or, wipe down the car with a soft cloth.
It’s music time!
Can he remember how to use a boom box or record player (tasks from the past or usually easier to recall how to do).
It’s “reading” time!
Will he flip through sports and automotive magazines that have lots of photos? Can you ask family or friends to create photo books (simple, in plastic sleeves) of them, him, sport hero’s, blast from the past pics. He may look through these over and over.
It’s video time!
If you can afford a tablet (iPad, or android) you can make only the apps you want available to click on. Then put a variety, but not too many, on the main screen - one for sports news, a channel for sporting events, one that might only play old sitcoms, a YouTube channel for bloopers, and one for a fix-it guy. After a bit you might figure out which ones he uses most and find similar stuff. You would want to hide the settings app, use parental controls to limit purchases. A high schooler (friend’s kid, church) could do a better job than I would setting this up.
There is probably a way to create a YouTube channel of your own that he could view on the TV, not sure how to lock out all the other channels but there probably is a way to do it. Your YouTube channel could be limited to subscriptions to the same type things I mentioned for the tablet.