It appears to be minor, though the test results have not all come back yet. He's having trouble coming up with words, but yesterday he couldn't talk at all, so at least he's improving.
I'm just home from being with him at the hospital all morning while my mother went home to shower and rest. Now she's at the hospital, and I'm home to shower and rest. I'm taking the overnight shift with him at the hospital tonight.
The hospital knows he's at risk for falling, and have told us that someone needs to be with him all the time. Of course, we'd be there in any case. If his hospital stay lasts too long, we'll probably hire some nursing assistance for nights. Hopefully that won't happen.