Crackers (1998)

Larceny, adultery, sabotage and treachery. Yes, just your typical Christmas with the Dredge family! Twelve-year-old Joey Dredge is in trouble again. Expelled for jumping off the school roof, he's haunted by his father's death and hates his mother's new boyfriend and his bullying son. Compounding his misery is the knowledge he has to spend Christmas with them at the family beach house. Things look grim until the unexpected arrival of great-grandfather Albert, fresh from a stint in prison. Forced to share the back shed with this swearing, farting and devious octogenarian, Joey's life changes. Between barbecuing the family dog, performing a self-burial and causing his intended step-father to consume a startling amount of hash, Joey learns a few life lessons from Albert, who despite his many vices may give Joey the strength to accept the past and embrace the future.