"trivialising traumatic brain injury which has been incurred whilst in-service to him"
They were really in service to the United States of America, not to just Potus, whatever Trump may think.
"I, ___, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; and that I will obey the orders of the President of the United States and the orders of the officers appointed over me, according to regulations and the Uniform Code of Military Justice. So help me God."
(Trump is a domestic enemy of the Constitution of the United States, but let that pass...)
They have to obey his orders, but it is not the same thing as being in service to him.
After another year please God or five if the worst happens, this Potus will be gone, and unless he is really successful in his efforts to destroy it, the Constitution of the United States will still be there.