I honestly can't think of anything else that would explain it.
He's under investigation for corruption, and knowing this, he decides to sell a U.S. Senate appointment. Oh, on the phone. Let's not forget that one.
But how would a brain injury explain his wife? And his aides?
I am having a hard time imagining how any one person could be so reckless. Or arrogant. Or crazy. But all of them? Together?
You mean that none of them said "Wait a minute. Aren't we under investigation right now? Maybe this isn't a great idea." But none of them did. So they are all going to prison.
I've heard the Nazi movement in Germany described as mass mental illness. This might be another example of it.