www.dentist.ihs.gov
There are open spots in western Oklahoma at Indian Health Service hospitals where the dentist would fill a civil service position through the federal government.
I second this idea. I walked away from private practice after eight years and was commissioned as an officer in the USPHS three years ago. I have been stationed at two IHS locations in Oklahoma (the second being a totally awesome 2 yr AGPR residency that I'm currently enjoying the heck out of). Civilian GS at federal facilities and civilian tribal hire at tribal facilities both pay very competitive salaries and offer decent retirement and benefit packages. The procedures you get to do varies by location - some tribal clinics have pros budgets while federals may not for example. Clinics also vary widely in size from single dentist locations to large clinics with 8-10 dentists and specialists.
Most IHS positions are in smaller towns within an hour or two of larger cities, and offer decent schools, low crime, and cheap housing prices. As a single mom pushing 40 with a special needs son, these things were as an important consideration for me as I am sure it would be for your friend.
There are also civilian IHS positions available in California as well as several other locations around the country. It might not be the most glamorous job in the world, but taking money and insurance out of the doctor-patient relationship is truly and deeply satisfying at the end of the day.
Finally, your friend is still in the age range (upper edge - might need a waiver if he waits very long) for USPHS commissioning. There's a sizable signing bonus (75k) with pay/benefits/rank the same as the Armed Forces and transferable GI Bill. We have considerable control over where we are stationed, and can work with a wide range of federal agencies (IHS, Bureau of Prisons, Immigration, Coast Guard, NIH, CDC, FDA, and more with the ability to switch between agencies if desired). The job security and retirement that would bring might be rather tantalizing to your friend right about now.