What is most interesting so far, is seeing illegal immigration from the Mexican point of view. There is no difficulty in getting to the US, just pay a 'coyote' $3,000 and you're there, reunited with your family or joining your friends. No difficulty either in getting jobs and settling down. Entire families and even towns had relocated to the US. So long as there needs to be no contact with the authorities, and for some there is never any contact, life is good, better than where they came from in Mexico. But... needing to go home it is impossible to fly, it has been to done the same way as coming in. And if the authorities find you, even (and this is terrible) if you are legal but don't have your id on your at that very moment it might be, as in the book, eight months of being moved around internment camps and no one knowing where you are.
The Mexicans (in the book) are very angry that the US treats them so badly. They feel they are entitled to go to their richer neighbour and make better lives for themselves. They blame drugs for the present poverty of their towns, drugs that the US want. They don't seem to want to address the illegality of their position, although Mexico is very keen on deporting people who overstay their welcome (from other Latin countries as much as tourist visas from the US).
And I am looking at it from the point of view of wanting to live in the US myself but being restricted to six months. If I stay longer and get caught (and last year there was an issue with Immigration who said I had stayed the entire six months when I had left months before, easily cleared up, but worrying nonetheless) then I get banned for ten years. I'm self-supporting, don't need housing or benefits and I don't want to work. So for the US it's money in, not money out. You'd think I would be a desirable immigrant, but no....
If a Mexican gets caught they mostly get the chance to apply to live there. It's no wonder the Haitians, beaten back so viciously by the border guards, instead of flying to Miami, went to Mexico and tried to cross the river. They had a chance that way, they would be turned back at MIA if they'd flown in. If I fly in I have all my papers in order, but still only 90 days at a time.
The US needs to have illegal immigrants, I don't see the euphemism of 'undocumented migrants' as changing the situation, it just sounds better and more sympathetic. If the farms had to pay minimum wage, the price of groceries would have to triple. If there were no illegal service workers, maids, gardeners, mechanics, fast food employees, but Americans wanting proper pay for their work, the cost of living would go up tremendously. So the US only makes a half-assed effort at keeping illegals out or deporting them. But there has to be a middle way.
I live on a rich island in the Caribbean. Here we have a system of work permits. We do get illegal immigrants, mostly from Santo Domingo (the Dominican Republic), same set up as the US, 'coyotes' and then they settle down in their communities, working in Spanish bars, maids, cleaners and prostitutes. Almost all of the prostitutes are from there, they are very pretty girls, and it's not something local girls on a very small fundamentalist Christian island go in for (at least at home). Like the US, the island more or less tolerates this situation, but deports people every now and again.
The book does not seem to be about 12 patients but about the author, a doctor, who goes through grueling cancer treatment himself and has a holiday home in Mexico. It's quite interesting, just not what I expected.