[Sleepy Speculator]

I'm probably wrong but itsn't there still the possibility that Takehito was Minato's father. Which would of course make Miya a sort of aunt to Minato.

It's quite hard to tell, but i think that Minato's mother seems to really avoid Miya, she had to call Kagari/Homora out on a mobile phone and pick him/her up in a limo off the street someplace random, and she gave Kazehana a message for Miya when she took Minato to M.B.I. which went along the lines of 'they won't be harmed'.

This implies that Miya may be more worried for Minato (a lodger) than his own mother, who would apparently do something strange to him.