Does he still drive? I would say if he can still pass the requirements for a drivers license, then he might be OK. I am not sure of your State's driving test for older folks.
I would be most worried about his mental judgement, reasonable reaction time/reflexes and eye sight. If you are comfortable there, then OK. If you are not good with those, then he should not be driving or have a gun. It would be time for him to live with a family member or in an assisted living facility.
We owe a lot to him and his generation, but we also need to realize when to start making the payments to care for them.
From the little information you have provided, it is hard to offer sage advice.