Straight A's (2013)

Years ago, Scott left Katherine at the altar to become a hedonistic junkie. She married his brother William, a successful Louisiana workaholic, who sired a daughter but probably not bright nerd son Charles and is serially adulterous on his many business trips. Now Scott returns on horseback, having lost his driver's permit, inviting himself and proving a popular, yet unreliable uncle for Charles. Making up with his father is impossible because of Alzheimer's. As Scott keeps surprising his family, his sad secret emerges.