I’m not familiar with Army insignia. On both lapels are what appear to be medical insignia - can one of our Army vets explain what they actually are?
Post #10, middle image, seems to be wearing the Caduceus lapel pin.
In post #1, he is wearing Aviation branch insignia and colonel rank.
In post #12, I think the guy in the blue uniform is a different person. The picture is blurry, but it looks like Medical Corps, which is the medical branch for physicians.