Rich, he did say "tough" and even clarified that to mean he said it was possible, and if the guy just keeps moving up, he might get a "12" handicap in relation to par but it's highly unlikely he'll get to a single digit index. The course rating will likely be low enough to prevent him from doing it.
If his driver goes 210 his other clubs don't go very far either. The best guys - who play the appropriate tees - who hit the ball that far, have good short games, and hit the ball straight tend to top out at a 12.8 index or so.
So I agree that it will be "tough" but not impossible.
I only said what i did because it is pretty similar to me. I made single digits 20 years ago (9.6 was my lowest ever) while just playing the middle tees on my home course (6500 yards - 69.4/120). Those are the tees I play in Men's Club tournaments, so most of the time they are what I play in casual rounds. Most of my friends do the same. I will play the back tees (7000 yards - 71.5/127) if I happen to get paired up as a single with 3 guys playing the blues, but that's pretty rare, and it puts a real strain on my game. I've never been particularly long - my 5I has never been more than a 175-180 club. The longest I ever averaged off the tee was about 250, and I'm more like 225-240 now (haven't actually calculated an average recently).