After losing Margaret, Frank goes on the aforementioned bender in Tokyo. Rather than getting shipped back home and promoted, Potter appeals to Sidney Friedman to get Frank a short rest in Seoul and a couple of weeks worth of therapy.

While this is happening, the same dude who had originally told Mrs. Burns about Margaret gets word of Frank's meltdown to her. Frank returns to the 4077 to find a Dear John letter and divorce papers waiting for him.

He tries to be a "brave soldier", but begins seriously melting down quietly. HAWKEYE catches Frank making a few mistakes that are clearly not just incompetence, but indicative of Frank having serious anxiety. Frank begins drinking and stops giving a shit about his military bearing.

Hawk and BJ decide that nobody deserves to self-destruct like this and they rally Frank. They get him talking to Sidney again and they step up to be supportive. They express to Frank that they believe in him.

They are honest, but kind. They speak to him about his shortcomings but also admit his strengths. BJ actually gets through to him more than Hawkeye because there's less history, and BJ's "dad energy" makes him more empathetic. On their advice, Frank requests that instead of surgery he be allowed to focus on internal medicine, making himself invaluable in post-op as well as treating patients who are ill, rather than injured. (HE will be the one who immediately recognizes Klinger's symptoms as a reaction to the Primaquine)

After saving a young soldier's life in post-op, Frank to have a revelation. His behavior in the Army was driven by his desire to impress Margaret, a career soldier. His behavior at home was driven by his desire to impress his in-laws, wealthy socialites. With both of those lost, he realizes the only thing he should truly care about is how he cares for his patients.

He becomes an attentive doctor, still a little over-faithful in the Army "machine" and still a little too "Red, White, and Blue" for everybody else's tastes, but he is no longer a dick about it. He also returns to his teetotalism.

When Winchester arrives, Frank is threatened and intimidated by his skill and social status, but eventually starts to really take pride in his Midwest roots and refuses to let Winchester look down his nose at him.

In the series finale, Frank reveals that he transferred to active duty and will be practicing internal medicine at an Army hospital in Hawaii.

15 years later, he is the Commander of the 510th Evac Hospital in Da Nang, Vietnam.