Question floating people

My mother in law experiences these things when sleeping since childhood, she explains it as people floating over her like right in her face right above her, she will scream and wake up. It just happened right now and she said a boy about 14 was floating over her with his face right in front of hers like super close , I asked if they have ever talked but she said she has always been to scared and wakes up. She says it feel like she’s awake and not sleeping. What could this be?