Genetic hair loss CAN skip generations (when you're looking for symptoms) and most likely comes from the female lineage rather than the male. Your BF's hair loss is probably not connected to drinking contaminated water in India. that can cause digestive problems, but not likely to cause hair loss.

Maybe he can cut his hair short, like a cropped cut. How does he wear it?

you can ask your doctor

or expert, it's a serious problem

I'm not so sure. The hair loss could be the result of bacteria, parasite or a heavy metal he could have ingested while afar.

"...he also..can't drink because everytime he does...he gets stomach pains..and ends up throwing up..."

Don't we all end up throwing up at one point? Stomach pains while drinking is also very common, some people don't go well with alcohol. Especially people that don't drink very often, I have always known stomach pains to be a common side effect of alcohol intake.
Everyone that I know basically who is balding some what tries to look for some other explanation or cause to why they are experiencing hair loss... but take a look at your boyfriend's head, do you notice specific patterns in which the hair is falling out? near the crown? or possibly at the front? that is where everyone starts. If he were losing the hair on the sides of his head, I might be concerned, but otherwise this is just another case of an unfortunate problem that still to this day does not have a cure, although humans as a race have accomplished things beyond the imagination, because it is sadly a big market, and people make a lot of money off of it. Marketers don't care about people as individuals if you haven't figured out that much yet, but what people will spend in order to attempt to fix a life long curse. Your boyfriend is now a target to these various creams or miracle pill sellers, life will be nothing but difficult until the day he finally buzzes it all off. THAT, is in fact the only cure.

If a person is not an alcoholic or doesnt like drinking it is common that they get pain in their stomach when they drink but somtimes these are just reasons to why they are experencing hair loss this looks like a bit of a problem it is genetic but as you are telling nobody in the family is bald so it would be better to consult a doctor who is a specialist in this field.....