Mouth Ulcers and various Problems

This is regarding my brother in law. I mentioned Mouth ulcers first because they really trouble him a lot. His other symptoms are as follows:
1) Vitiligo - His whole skin is now white though not uniformly. He is unable to bear HEAT or SUN. Which cause severe burning.
2) Mouth Ulcers. He was advised to take Nitric Acid 30 for a few days every time it happens and that helps a bit. The ulcers are also on his gums and his whole mouth is dreadfully sore. Sometimes his inner throat may be affected too, all the way to his neck. Burns a lot. What he wants to find out is why do they keep on recurring.
3) Pain in the nape of neck, maybe due to his sitting with the nape on the bedpost. There is a knot there now, and he also feels nauseous at times.
4) gas, and smelly stools which are a bit oily. This is a recent trouble.
5) his signature has also spoiled. two are rarely the same.
6)His short range memory has also spoiled. He may go to someone to ask something but by the time he reaches - 1-2 mins later, he has forgotten it.

He is a 48 yr old man, loves chillis, but avoids them as they cause burning in rectum and stool. Prefers to avoid arguements, but will shout at his wife. Salt intake is normal, no craving for it. His diet is quite bland. Few spices. He is a pure veg, may eat cake rarely.

Joe, walkin, Pankaj, Girilal, sazim, John all of you posting here, can he be given relief in any way. He is not seeking anything for his vitiligo as his whole skin is now white.