Final Offer by Lauren Asher

Callahan I'm the Kane brother everyone gossips about behind closed doors. Trust fund brat. Washed-up athlete. High-functioning alcoholic. No one knows the real me but her. Lana Castillo—my childhood best friend and the only woman I ever loved. When I broke her heart six years ago, I promised to never return to Lake Wisteria. I kept my word until my grandfather's will changed everything. To receive my inheritance, I was tasked with spending a summer at the family lake house before selling it. The request was simple in theory until my entire plan blew up on the very first day. Turns out Lana doesn't just live at the house, but she claims to own it, too. Alana Falling in love with Callahan Kane was a mistake. He told me so before destroying my heart and our friendship six summers ago. When he promised never to come back, I foolishly believed him. But then Cal showed up again, intending to sell his grandfather's lake house. The biggest flaw in his plan? My name is on the deed. Final Offer is the third and final book in a series of interconnected standalones following three billionaire brothers.