Has anyone else experienced this???

My bf has an odd thing happen to him and I’m jw if anyone else has experienced this/heard of this happening? He’s 20 and works third shift so he’s tired a lot during the day. He has this thing happen where he gets really sleepy during the day and then eventually goes to sleep and will sleep for several days at a time and no one can wake him up. He says he feels like an out of body experience right before it happens and he will wake up randomly and do things but wont remember them. The last time this has happened was 2 years ago but he said he’s starting to feel this way again. Any options on this??