That is a good question...it could be a number of things. I would suggest that he visit his physician for a correct dx.

My vertigo / fatique and sleepiness are mostly due to inner problems / sinus infection.

~Zig

I am also experiencing the same thing. I could sleep all night but still be fatigue. I also am constantly dizzy. I feel like I am on a boat. I also have no appetite. I am also 3 months post partum. I've been to numerous doctors, and they have not found anything yet. I will keep searching.

i feeel th exact same and hav just been diagnosd with anxiety and stress..im constantly dizzy and got really bad head aches feel nausea.. do u experience like faintness?