"Meanwhile he is in is 70's. I think his prime is well past for leading our nation."
Thank you God.
The information is from Wikipedia, so TIFWIW, but it seems he was mobbed, beaten and bayoneted upon his capture, and his shoulder was broken by a rifle butt.
After that he was beaten and tortured pretty much daily for five and a half years. At one point he did apparently break and sign a propaganda statement (written in Vietnamese). For whatever reason, the NVA decided that they couldn't use it - probably because it was in Vietnamese - and they wanted him to sign a second statement. He refused and was beaten and tortured some more for refusing.
He was offered repatriation early on, when the NVA found out that his father was an admiral. He refused and spent the next five years getting wall-to-wall counseling from the guards.
Signing the statement wasn't treason - anyone will break eventually under torture. The practical interpretation of the Code of Conduct anticipates this. The standard is if you break - get back on the horse and try again.
Bottom line is, he went through a special circle of Hell that most people cannot even imagine. However, as the saying goes, that is going to leave a scar. The mental scars are what I suspect lie at the root of his behavior, which some describe as "maverick", others as "mercurial", but to me are plain unstable.