I saw your post at 2 am before falling asleep and from the snippets you put here I wanted to punch him but anyways, I did read your story and I can have a better understanding of fostman: he is good but tends to be at not funny jerk sometimes, specially towards women (I ntoiced the jerk comments comming from him were directed more toward women tahn men) I think he has potential to be funnier even if being jerk-ish (he reminds me a bit to Gojo) I think hes a good character for your story tho, you are managing heavy stuff there.
Like this to certain point:
Summary
They are calm and chill most of the time but to him they would retort with violence XDDDD