I start to think there must be a different aspect to Shiro's mother's death, judging by his dad's attitude to everything. But why he doesn't explain everything to his son lol, what a stubborn man
Also on page 12 "...cooking it quickly with high heat using coke." Should it be "coal"?
Edit: Ok, I look up and there is indeed a type of coal name "coke". https://en.wikipedia.org/wiki/Coke_(fuel)
The more you know.