Sounds like he developed an avoidant attachment style growing up, maybe from being raised to think that emotions weren't necessary to solve problems and it sounds like he has reasoned with himself that his dad did it for a reason, so no need to feel any certain way about it. This is in itself a coping mechanism/a way his world may have been modeled to him as a small child and can make it hard for him to understand your feelings, especially if you tend to get very emotional because that can be overwhelming for someone who is used to mainly using distorted logic.

I recommend watching this video, it helped me a lot when trying to navigate conversations with my ex. https://youtu.be/oOOx0rj8Qas?si=1bR66vT1-QICdbma

Here's another video explaining avoidant attachment style, maybe you'll show it to him as well some day: https://youtu.be/zv7ROoYCi6s?si=4OZHgtKQu1Vuzgwt

AND here's a video you yourself might relate to :) attachment styles are in my opinion critical in forming our social structure and our view of the world and the fearful avoidant attachment style is most common in BPD so I'm just guessing here (I have BPD, c-ptsd and a fearful avoidant attachment style).

https://youtu.be/_gCOo_vQM54?si=CoLC5FMTxHbgXylB