Keep in mind the symptoms of stroke. There is a 3 hour window where they can reverse much of the damage, using a clot-busting drug.
The face often droops on one side, the speech is sometimes slurred. Ask him to smile and see if it's crooked, or to raise his arms and check that one doesn't reach as high. Then call 911 if you see the signs.
Wow David, you constantly amaze me with your wherewithal, 2 strokes, liver disease and transplant, no caregiver, and you still work at a physical job. And you help so many folks here.