Keeping Up with the Steins (2006) on Netflix

After slick Zachary Stein's lavish bar mitzvah (a Titanic themed event) was a spectacular hit, even by Brentwood socialite standards. His dad Ari's rival as Hollywood agent, Adam Fiedler, is determined that his boy Benjamin's bar mitzvah must outclass it. Ben is insecure and hopes to divert dad's attention by sneakily inviting his hedonistic paternal granddad, Irwin. Irwin abandoned still bitter Ari and his mother, granny Rose, but she welcomes Irwin back. Soon the Irwins bond with Ben and rather paternally prepares him for the rite of passage, ultimately inspiring a different approach as well as a more confident attitude.