Next of Kin (Next, #1) by Hannah Bonam-Young

When people pleasing Chloe learns that her birth mother has unexpectedly had another baby, she doesn't hesitate to become a next-of-kin guardian. But, when she fails to pass Child Protective Services' financial evaluation, she is faced with a choice: see her baby sister placed in foster care, or participate in CPS' new initiative, TeamUp.

Enter Warren, a surly mechanic's apprentice attempting to get custody of his deaf fifteen year old brother after failing CPS' housing evaluation. The two stranger's immediately clash but agree to live together until Warren can find housing elsewhere and Chloe can further grow her freelance career.As their lives further intertwine, Chloe and Warren both realise that they're far more similar than they could have imagined. What started as forced, begins to feel natural, and far less lonely.

Chemistry soon intensifies beyond what either of them can stand, but they must each decide if what burns between them is worth risking their arrangement.