Kido's Fate

I've watched this series a while back and just rewatched it again. I just need someone to make sense of this for me. I don't get why Kido didn't use his political pull to go back home to Japan with his son. Instead, he agrees to stay with the Yakuza. I get the honor part and all that as Kido has always been a person to stand by his honor and duty. But idk, this doesn't make sense in the grand scheme of things.