He's going to have to change the way he eats first. If it's IBS (and even reflux0 his stomach and intestines need to rest. For the first day he needs to stick with clear liquids (anything he can see through). Stick with soup broths,some low sugar jello and either diet sprite or small amounts of sprite. Diluted gatoraid can also be used. The more days he can stand of this the better. When he can't take it anymore he can have small amounts of eggs, toast, bannanas, rice and apple sauce (it's called a brats diet). At this time he should take a digestive enzyme. It's made out of plants and you can buy it at the health food store. He can also use either a probiotic to help the good bacteria in the intestines or he can use garlic capsules to kill the bad bacteria. I use the garlic. It's cheaper and works better on me. After a few days of this he needs to take a multi vit. and a balanced complete b vit. It helps with the gi muscles. He needs to take it with food. Then as he feels better he can add new foods one at a time. If he adds food slowly he might be able to find out what foods he can't eat. With me, it's milk and nuts. With my sister it's alcohol and steak. It can be a little or alot. If it's IBS it's going to take a life change. Don't give up on the nexuim untill he's taken it for at least 4 months. For reflux he also needs to saty away from high acid foods. Also, IF THERE IS BLOOD IN HIS STOOL, HE MUST SEE A DOCTOR ! I hope this helps. If it's IBS I know how painful it can be.