beta
The dad prolly experience something similar like what he did to tomoe, that's why he neglected his son. The dad is prolly wired in his brain that if they serve no purpose in the family's business then they aren't that important. He just doesn't know how to handle something that wasn't taught to him or given an environment to learn that "unimportant stuff" is okay, totally not justifying his actions. Just my speculation of his character after rereading this manga again