Trees Grow Tall and Then They Fall (2005)

Teenager Ellen moves in with her alcoholic father for what seems like the hundredth time, into a tiny trailer with his ex-wife, Hilly. Ellen soon discovers Hilly is still married to Roy, who was mentally disabled in a logging accident. Brokenhearted, Hilly refuses to see or hear anything about her husband, but Ellen can tell Roy is still lucid. So when her father skips town again, it falls to Ellen and her new boyfriend to rescue Roy and reunite Hilly with her true love.