The Beloved Dearly by Doug Cooney

Ernie is a twelve-year-old tycoon, always on the lookout for a fast buck. This time he stumbles onto a money-making bonanza: pet funerals. He hires Dusty to decorate the burial boxes and Tony to dig the holes, but his prize find is Swimming Pool, a tomboy who delivers a crying jag not to be missed. Business goes through the roof - until Ernie loses Swimming Pool over a raise and the whole venture unravels.