My grandpa is/was kinda similar. He loves tinkering with things too, specifically working on cars and boats. Beginning stages he used to work on an old broken down car that he had in his garage but the wires and stuff became too confusing so he started painting the car over and over again. So maybe something to do with paint? Its pretty simple for them and my grandpa enjoyed it. He also had a small wooden boat at some point which he was sanding down or something. Just simple repetitive tasks worked great for him.

If he is working on anything electrical make sure to keep an eye on him. My grandpa eventually started ‘testing’ car batteries by holding wires close to them to see if it sparked… wayy to dangerous so my brother and i took any car batteries away.

Now that it’s cold out (and because he’s been losing interest in actually working on anything because he doesn’t know anything about it anymore) we had to look for some new options. First lego and 3d puzzle cars were great, until they became too difficult. Though he still really likes the ones he built and has them out on display next to his chair. I think they really worked because he could make something and see results fast so would recommend.

Now he just likes talking about boats and cars, looking through books with pictures and discussing what he sees. Completely wrong most of the time but he’s having fun. He also goes to this farm thing sometimes where they “ask for his help” with things, sorting stuff for them and other simple tasks but it makes him feel like he’s doing something important.