The mom is a badly written plot device. First she smacks the taste outta Sora's mouth at the drop of a hat, but then goes "alright, do what you want" when she displays any resistance. The whole arc pretty much went like:
"It's me, Evil Mama! She's coming with me!"
"No, Evil Mama, I love her!"
"No, Evil Mama, I want to stay!"
"Curses, foiled again!"
[kissy time, applause ensues]
I get that forced drama is the most popular way to extract a climactic confession in yuri manga, but this was just too on the nose lol. It even happened at the most opportune moment possible; just in time to avoid the perfectly unstrained confession Ayaka was going for earlier.