prerequisites for working at a data center

My apologies if this isn't the right forum. I have a friend who has been out of the labor force for more than ten years caring for a family member. Although he's never worked in IT, he's intensely interested in hardware and network infrastructure, having spent much of his free time building Linux servers, setting up home networks, tinkering with virtualization, etc. Now that he's preparing to return to work it occurred to me that he might be able to turn his hobby into a livelihood. He's in North Carolina's Piedmont Triad where there are a number of data centers, and I'm hoping to find recommendations and resources he can use to make himself a good candidate for entry-level job openings. Thanks in advance.

With modern datacenters, there are different jobs:

1. Actually building the thing: normal construction work plus pulling fibers without damaging them and terminating them. Some building contractors can do the latter, but most won't touch it, so there is a specialist niche, but that is a traveling job.

2. Hands-on work for maintenance. Very few jobs, but on-site, so with a fixed location. Mostly pulling out and replacing fans and harddisks, usually no configuration work except maybe resetting a BIOS.

3. Actual server management. Sitting in an office with less aggressive AC settings than the actual datacenter, so it's actually comfortable, and controlling everything remotely, creating tickets for the local people if something breaks.

These are pretty much separate, so there's no path from hands-on work to doing the actual server management. No one in that stack actually does any system administration, that is on the customer side.