Sorry I didn't see this thread when it was started last month, but glad to read it's getting close to the happy ending.
I was on the receiving end of this transaction (for my 50th, mrs mcmnky got me a Data East Star Wars) so it was a fun read this morning, imagining the similar conversations my wife had making her purchase. In her case, she didn't have the luxury of knowing which machine I'd want. I didn't know I wanted one until I had one!
I'm confident you came to the right place (pinside) and you've gotten good advice. It's late in the game, but I'll add just a few things: hopefully in your purchase you prioritized a machine that is fully playable but maybe has some cosmetic issues over one that looks great but has mechanical problems. Being able to play pinball will make up for pretty much any imperfections it may have. In my case, my DESW was obviously not home use only (and I suspect wasn't properly padded for shipping) so there are plenty of scratches and scars. But it plays perfectly. Every bumper pops, every bulb lights, every target drops or spins or whatever it is supposed to do. Can't ask for much more from a 30-yr old toy that's been played with.
Next, assuming you followed my first point and are getting a mechanically sound machine, I would worry too much about maintenance. Yes, there are a lot of moving parts and things will break, but most of things that go wrong can be fixed with not much expertise. The most important skill dear husband will need is the patience to read through pinside threads where almost every issue he encounters will have been had and solved before.
It's nice to have a relationship with a local professional who can help with the more complicated repairs, but to give you an idea of my experience, I was someone who owned a multimeter and soldiering iron but hadn't used either in probably decades. I don't consider myself particularly handy or mechanically inclined. But in less than 3 years with a pinball machine at home I've: cleaned and waxed the playfield, installed Cliffy's Protectors (thin metal that protect the edges around holes where the ball goes in and comes out), replaced a broken power switch, replaced the RAM and CPU, upgraded the sound board (PinSound) and display (ColorDMD), fixed some uneven plastic parts (turned out a supporting screw wasn't screwed all the way), and replaced a metal ramp.
My last suggestion is to include 2 things with your gift (as if TAF isn't enough!): 1. new balls. Balls wear down, and a bad ball does bad things to the playfield. New pinballs is something he will always need as long as you have pinball in the house.
And 2. a link to pinside! He'd likely find his way here quickly (like I did) if he searches the web for tips on pinball maintenance, but a head start doesn't hurt. I'd also strongly recommend looking for "Vid's Guides," longer threads started by user vid1900 who is absolutely amazing for expertise and a willingness to share that are both seemingly superhuman. He might start with Cleaning and Waxing Pinball Machines, but there are also guides on rebuilding pop bumpers, flippers, replacing electric cords and plugs, and more. If it's something the home owner can do to maintain a pinball, there's probably a Vid's Guide on it.
https://pinside.com/pinball/forum/topic/cleaning-and-waxing-pinball-machines-vids-guide
Other than that, have fun! It's big, it's expensive, but in the end it's a toy that's meant to be played with and enjoyed.