
He needs to fire Nishi. The guy has never drawn and refuses to do any art assistant tasks. He also is useless as a personal assistant as he causes trouble with the kiddo, and he's not doing household tasks either. He's not assisting with anything. There's a middle ground between leaving him stranded and homeless at the train station vs paying him money and giving him room and board. That middle ground would be firing him, but also driving him back to the city where he can return to his house and get other jobs.
It's a business marriage, not a real marriage. That means it's an excuse for both families to become allies, but even though the two are family now as a result they aren't a real couple. They don't do things together that would ruin childhood.