What make and model was his last bike?
If he's going to put his foot down in a curve, I'd strongly suggest a riders course for him before he gets back on a bike.....and then an advanced rider's course. There are several right there in the bay area. There are several street bike courses on this page and I know that one of the instructors is from Sacramento....as a matter of fact, the first course listed is "street bike cornering".......
https://www.superbike-coach.com/riding-programs And right across the bridge from you.....
https://www.sheriffacademy.com/class.php?id=103I'm certainly not a riding expert but my experience is I road in the dirt on the canal banks in the Sacramento valley as a kid and then on to the streets at 16. In the dirt we may throw a leg down in a curve but I'd never do it on asphalt or concrete.....there's a high probablitity that it's going to cause a whole lot more damage to the body than just road rash.

Most bikes the floorboards or pegs are designed to fold up if they scrape. If it's going to go all the way then the best thing is to get away from the bike. JMHO for what it's worth. The other thing they teach in all the courses I've attended.....look where you want to go, not where you're at. That alone has always saved me from going in to a corner to hot.

Not saying I haven't scraped.....to many here have observed that for me to make that claim but the floorboards will fold up.
You have a riding instructor on this forum that lives just a short ride from you.....maybe he'll chime in here.