Ryuunosuke name means a strong person, but also a change and forward thinking, ironically that's how xe acts.
Mr. Mogumo father was physically violent in solving his issues and as him now, didn't try to understand his ways, but somehow they managed to understand each other after he grew up, this is commonly used misconception, there's hardly any evidence of evolution of themselves through reflection of past issues and seeing how they had a reason as not everyone is doing things in the eye6of parents.
Ryuunosuke would turn out the way xe is regardless if Mr. Mogumo would be there in the 2 years of absence, moreover it WOULD most likely end more tragically as Mrs. Mogumo was more passive but still put a pressure on their self leading to self harm which would end in suicide...
Tetsu couldn't stop his father from physically abusing his sister Satori when he was young, violence is not the answer but dealing with Mr. Mogumo seems like it's the only option...