Also, wouldn't it be funny if she deliberately seduced the dad to get her shota back?
Definitely one of those "it's too improbable to simply be a coincidence" situations, she's obviously got some screws loose and it's easy enough for her to figure out his name/family to set everything up.
Also she wasn't in the least bit scared/nervous seeing him at the dinner with dad and went straight to "bet you like curry huh?"
I'm guessing that soon enough we'll find out that his experience with her unlocked the next level of her young guy fetish to include the mommying and pushed her to yandere-level obsession with getting him back.
We'll have to see how they end up towing the balance between being "Mom" vs. "Love interest" but given this opening it ain't gonna be wholesome. There will be nice "mom" moments sprinkled in as part of her predatory strategy to have control over him which just adds layers to the incoming psychologial abuse, and MC being forced to NTR his dad will only mess up his brain more.
BUT that's just the obvious speculation, maybe it goes a wildy different direction who knows.