my dad also spent years in vietnam. I think it's impossible for him to relax. it's almost as if it would be taking bits of his flesh with red hot pokers.
illustration of Lizard's dad's rigidity:
(back when my grandmother, his mom, was still alive)
my brother John: "mom, have you ever heard Dad fart?"
my mom: (shakes head in chagrin)"what a topic! but you know what...I don't think I ever have!"
brother matthew: "I sure never have. that's how disciplined he is!"
sister elaine: "grandma, when dad was growing up, did you ever, ever, hear dad fart?"
grandmother burr: "never, in my entire life."