How much food is he eating at night? There could be digestive issues. I have nausea in the morning too, and more so when I have eaten alot of food that tends to move slower through my digestive system. Does he have any constipation? If so, try a magnesium supplement. Also breathing exercises are good. One previous post mentioned the metaphysical cause being "sick of life" and that is a good thought, as we all suffer from the human condition and the good and bad in life and it very much affects everything about us particularly in our physical body. Our breathing patterns change as we progress through ups and downs in life but we don't notice how "off" our breathing/life force energy gets. By working on correcting the breathing, you can open up the emotinal blocks, digestion will flow more naturally too. Yoga masters know this - I'm just learning about breathing and yoga now myself so I don't know too much yet, but you may want to look into that too - there are lots of books on breathing.
Another thought...How about doing a cleanse? This will clear everything out, sounds like his gallbladder and other organs might be overloaded and a cleanse is a good way to hit the reset button on the digestive system and the immune system as well. And the mental/emotional state as well. You should check out the work of Dr. Gabriele Cousens, he is in Arizona, US. He has published books and has a website, I don't knwow what it is but it is called the Tree of Life rejuvenation center and you can probalby google it.. There is also the Stanley Burrows master cleanse which is basically the lemonade cleanse and you can buy a book on how to do it from amazon.com for very little. I haven't done it yet but I know people who have and they say they feel so vital and alive after a few days on it. First though I would check in with a naturopathic doctor before starting any cleanse so you can get any tips and pointers such as things to look for, what you may experience, etc.
good luck.