[g.willikers]

One thing he should absolutely be doing is hand exercises.
Yeah, they hurt, but without them the joints get worse and more stiff.
Have him use a soft foam ball and squeeze it while holding it out like a handgun.
Exercises loosen the joints and cut down on the pain.
Part of the pain is caused by the resistance to movement.
The more flexible the joints are, the easier they move and the less painful.
It's a vicious circle.
If he's not presently exercising his hands, he will not like it at first, guaranteed.
But he will thank you for suggesting it, in the long run.
Old age is definitely not for sissies.