This is difficult, but basically they need to just work to find a job until they catch a break.
For any future children you may end up helping with this, I’d say tell them now to get this experience WHILE they are in college. It helps immensely, and in a college town setting, it’s alot easier to find a place that will let you as a student get your foot in the door, including working for the university.
Networking, at this point is huge @Jude you need to spread the word to people you know, your nephew’s parents do, people at church (if that applies to your family), and pretty much everyone you know until someone can get him that first job.
Also, your nephew should go back to college (not to classes) but to the campus where he can find on-campus interview days, and college career fairs both of which bring HR people that fully expect and are looking for people like your nephew, without the relevant experience.
Many of my friends were recruited right off campus for companies that have programs that groom college graduates with the knowledge but without the experience!!!