Responses
He wouldn't have to give any power away in that marriage with Weiner. If anything, it might give him more power. He could have also viewed Weiner as someone easily controlled by him, so he wouldn't cause much issue like other nobles and their families. That, and eventhough he was a big classist, to others Weiner is a decorated war hero who has earned some respect. He also cares for his daughter above anything else, so if she said she loved him, he'd probably allow it.
What I really don't understand is why the father of the Fl allowed her marring him instead of the other noble (the blond one). Being the father a f*cking classist.