I think he just grew up the hard way, which he truly wasn't meant for, and it resulted into him never wanting to show signs of weakness/affection in general. But if he would've been treated fairly, I think he would've turned out really nice.
I do also think that the homophobia stuff in the army must've not helped either :/
(though he had a crush on Kieran, and he had fun playing with Cain 🐶 so... yep he does have a soft side)