The Guncle by Steven Rowley

Patrick O'Hara finds himself taking care of Maisie and Grant (his niece and nephew) for the summer after their mother passes away and their father, Greg, goes to rehab. Patrick is not keen on the idea, since he's spent the past four years hiding out in his Palm Springs home away from the acting scene in Los Angeles. Patrick was on a very successful sitcom, but retreated from public life after the love of his life, Joe, was killed in a car accident. In The Guncle, Patrick regales Maisie and Grant with his "Guncle Rules" and introduces them to his laid-back, unstructured lifestyle, while the kids' presence helps Patrick to heal. A fun summer read.