Hi there -
There are so many potential causes of this problem that we'd need to know a lot more about the patient to even begin to guess at the cause. This problem (hypersomnia) can be caused by genetics,
depression, sleep apnea, essential narcolepsy, drug use/abuse, and even
mononucleosis.
If your boyfriend snores a great deal when asleep there's a good chance this is due to sleep apnea. If he's depressed or taking sleep-inducing medication, then that could be the cause. If he has mono (which would also most likely have other symptoms, including fatigue during awake time), he would probably need the rest, but would also be fairly easily fatigued while awake and functioning.
Which brings us to the next question: is he tired when he's awake? Or does he simply sleep until he's awakened? The answers to these questions, as well as the others above, would be necessary to even begin to guess at a cause of this. Probably the best thing would be for him to bring this problem to the attention of a doctor, have a complete physical with lab work, and try to rule out the more obvious causes.
I hope this is helpful to you both. Good luck to you. Please follow up with us as needed.
