No problem, I know you mean really well. So did the people who bought me some crappy items gathering dust in the corner 😅

If they’ve already identified objects, that’s great though. It sounds like their arthritis is limiting their grip strength, hand open/close action and maybe twisting objects is the problem too. Perhaps instead of a new gas cap, a more universal tool like a smaller lever clamp might be useful for multiple things and can be kept in the car.

Not professional advice though, hands are not my area. Good luck!