First, clarify what his goals are.
Google “Pavel Tsatsouline Dad Deadlift” and click the StrongFirst link that says “My father’s deadlift program” - see if your grandfather likes the idea of trying to join the 70-year-olds-that-can-deadlift-bodyweight-plus club, and ask if that program itself appeals to him.
If it does, I think we’re done here…
If he has the appetite for something more complex, a 5/3/1 2-day template would seem to work, assuming that he likes doing the powerlifts.
If he just vaguely likes the idea of lifting weights but is turned off by heavy barbells, a different path may be required.