I don't think the mom's plan is going to work , especially now that her sister in-law is aware. How often does trying to placate someone hoping that they'll be satisfied ever work out in manga? Haha.
@alhazred: I'm assuming the latter. Seems like Kongou would love them all unconditionally and understands the changes that Phos went though, though it'll be interesting to see if the other gems see Phos as a traitor or something next chapter(s).