I don’t know about the state, but county public law in CA provides for “mandatory retirement” at the age of 72. Since this SL debtor is already 71, I see his state pension (of which a portion is already offset by SS) AND his SS garnished until he dies. Not sure it will come to $3K per month, though.
There is absolutely no excuse for a person who has been a dentist for ~30 years to still be carrying any kind of personal student debt at all.