Dream a Little Dream (1989) on Netflix

The lives of a crusty old scientist and a bratty, teen Michael-Jackson-wannabe are about to intersect in a paranormal way. Coleman Ettinger seeks to break down the door of reality through studied dreaming; Bobby Keller wants Lainie Diamond, the girlfriend of his high school friend Joel, a handsome school jock. As Coleman persuades his wife Gena to join his experiments, an accident knocks their bodies out of existence, along with Bobby's consciousness. Coleman's consciousness winds up in Bobby's body while Gena's ends up buried and asleep inside Lainie's. Only when sleeping can Coleman contact Bobby and elicit his help in putting things back, except that Bobby smugly prefers limbo over his aggravated life as a modern teenager.