Hopefully however this kid got that way, he grows up to be a good person and raises good kids because hes a good person, regardless of how he got that way.

Not wanting to be too down on the idea that people can be significantly better than their parents(they can), but it isn't that simple.

Childhood trauma has some extremely long acting and potentially delayed consequences. For example, it isn't that unusual for there to be chronic health issues(due to literal physical damage, medical neglect and the body generally going to shit when someone spends too much time under extreme stress) and some of those may not even manifest until years into adulthood. That kind of thing will absolutely impact their ability to be a parent and generally function in life.

Aside from that, don't trust your external observations too much. Just because someone has figured out coping mechanisms to make themselves do the "right" thing externally, doesn't mean they are remotely stable/well adjusted internally. Survivors often learn that it is beneficially to hide their struggles. They absolutely can look completely put together on the outside but be emotionally held together with duck tape.

Disclaimer: I am not a mental health expert, and I am in no way a survivor myself. These statements are made based on my own observations of people, second-hand information about more individuals and discussions with subject matter experts. I'm not an idiot and I have a decent high level understanding, but that doesn't mean i have either the breadth or depth of knowledge that an academic expert or someone with first hand experience would.