Wait are they related?? In the 15th chapter she said that her younger brother slept with h...

no they're not biologically related the ml dad remarried

Ooooh ok tysm I stopped reading after the 15th chapter so I might have missed something later on

I was skipping long ass dialogue and then when MC's call the seme "uncle" I still didn't notice until that woman said "mom"
I was like damn I can't drop this right now...it's getting interesting

I mean is it even incest?

They aren't biologically related nor grew up together. They were strangers who were forced to live together and happened to form a bond..

Since they are not biologically related then it's not incest (plus like you said...they didn't grew up together so I don't see anything wrong tho)