He did. He enjoyed giving the order to shove feeding tubes up assholes. I can provide a link from Harpers.

He is shit with legs.

He worked there for sure, but we don't know all the details of what he did there. He probably just advised the actual torturers that what they were doing was legal.

Well, he did use his position to gain the trust of gunatanamo prisoners and when they told him what was particularly stressful to them, he passed that info on to make conditions worse for them. Like, a prisoner would tell him "we usually pick the vegetarian option because we think the meat here isn't halal" and a week later, no more vegetarian food option. Things like that. There's also a pretty harrowing account of how he oversaw hunger-striking prisoners being force-fed. People screaming and throwing up and shitting themselves in agony and he stood next to that and laughed. I honestly believe that if he didn't join the navy to live out his murderous sadism, he'd be a serial killer with a collection of human body parts in his basement. Guy's a complete fucking monster.