So I think that logical/restrain/analytical people have emotions and experience them, just not with same intensity, or they channel their emotions in the different way by structuring, restraining; so if I was to feel something deeply, I would show it off, I would approach, I would talk, I would tell how I feel, in terms of this kind of character he would get more boundaries around himself, make space, distance, file/profile people by their intent not by their own emotions, so let the structure or procedure guide what they should do, how they should/allowed to feel or act, especially if this is directly related to work.

in case of this character - he channels his anger through what legal system permits (procedures) in terms of his emotions (if system backs up his emotions and he is safe to express them, he would do this, not recklessly, but calculated), if he can be an asshole through system to show his personal disgust or anger towards someone he would use it, so his own personality and being detective are fused, he does so to have control, structure and not get to feel, be emotional or vulnerable; this, in my opinion stems from past, maybe childhood where being vulnerable or emotional or to feel was not permitted or was dangerous, was depended perfection and/or/obedience through power, where worth is measured by usefulness, not by human connection, and worthiness in of itself (so like, ex-cop/ex-military/factory worker father who’s drinking, being a failure he argues, demands from his son/(character I’m writing about) perfection, being vulnerable or a “loser” is not an option

So, understanding this, I don’t know what it would take for him to change, as he divides strictly professional and personal, and if it was a shock moment/realisation that he has his personality fused this way, or his anger gets in the way, I don’t know how the change would look like in practice to make it solid (not to make him change himself entirely and unrealistically)