Jolly (2009)

Andy Silverman, a forty-seven-year old Jewish man, is having the worst holiday season of his life. His best friend is dead, his business has collapsed, he is undergoing chemotherapy, and his overprotective sister has convinced a court to give her complete control over Andy's disappearing finances. Depressed and resentful, Andy is reduced to merely getting through the weekly cancer treatments that leave him weakened and sick. So when he is approached by his one remaining friend to pretend to be Santa Claus for the sake of a little girl named Mikaela, Andy emphatically refuses. But then Andy meets Mikaela, and suddenly, his life takes an unexpected turn for the better.