Mini Skirt love (1967)

Billy is a teenager and enthusiastic photo hobbyist who takes pictures of his mother carrying on with another man, but is too naive to realize his mother is engaging in more than innocent horseplay. When he innocently shows his pictures to Daddy, he unwittingly starts a melee that ends in Daddy's accidental death and Mommy's mental collapse and confinement in a hospital. Enter Aunt Janet, Daddy's sister, to take care of Billy. Supposedly a frigid woman who "can't stand men", Aunt Janet is nevertheless loving and affectionate with young Billy, and when she sees the fatal snapshots, she even takes their relationship to the next level. But can their happy life together survive the return from hospital of a still-disturbed Mommy?