I don't share the author's despair at all.
Trump isn't going to stop immigration. Even illegal immigration. He builds a wall, they'll dig tunnels; you've heard it before.
The white electorate is shrinking. Trump's coalition is unsustainable. When these people realize that coal jobs are NEVER going to come back (solar is getting too cheap and the benefits to consumers over coal is too obvious), they'll have second thoughts. Automation, fueled by AI, will become ubiquitous, and soon the only jobs left will be tech jobs, creative jobs, managerial jobs, etc. The manual labor jobs that white rural America reveres are dead. Their way of life is not just dying, it has been terminally ill since the start of the 21st century.
People can only sustain active hatred for so long, it will soon fade away into apathy and acceptance.
It is up to the Democrats to reorganize under Bernie Sanders' leadership. They need to bring these people, with all their warts, into the fold. If we can create new jobs with new technologies, we can stave off the worst of the coming automation revolution. But eventually we will need to shift the paradigm of how we think about jobs, labor, and what is necessary for a society to function.