Heroine works at illegal hospital. Part of series about all the siblings.

[Moon]

Hey,
I’m looking for a book where the hero is a mafia guy according my memory
And the he think the heroine is doctor or something like this but actually she volunteered in illegal hospital
I think it’s part of a series where every book is about another sibling
And this book is about the only sister (all other is about the brothers)

[Lisa]

Are you looking for the monster by lj shen?