Well, we can't bend the rules where the children are watching, at any rate!

Best of luck with your rhetorical strategies, Lucius! I'm sure you'll find a way to persuade him.

How many children does he have? He's probably reluctant to give it up because of the hassle of relocating a large brood. Perhaps if you offer up a location with ponies for all the young ones -- taking care that the eldest girl hears you make the offer -- she'll manage her father for you. Should more reasoned options fail, at any rate.