As a military retiree, I'm sure Trump didn't pay off this doctor. There would be no need. As Commander-in-Chief, Trump has Dr. Rear Adm. Ronny Jackson's career in his hands. The doctor is a U.S. Navy Rear Admiral appointed to the position of Physician to the President by Obama. When Obama left, the doc was left caught between a rock and a hard place because unlike the lucky Federal Attorneys who were fired, Trump didn't fire the doctor. Even though he is Physician to the President, the doctor is still active duty Navy. If he doesn't want to ruin his Navy career, at least for now, even though he's not a politician, he's got to play Trump politics. This isn't a matter of money in the bank. It's a matter of a man who in 1995 decided to serve the U.S. in one of the most honorable ways possible only to inadvertently get caught up in "The U.S. According to Trump". It's obvious he was told what to say, but he was probably thinking the same thing I was thinking. Trump's years are much more limited than his.
Before anyone suggests it, no, he can't just say "I quit" unless he wants to ruin the rest of his life. For the first time since 1979, this retired enlisted person feels sorry for an officer.