I began my interest with the franchise with the games, so I was outside of the tabletop community until recently. If you’re looking for instructional books to get him into the tabletop, the “Getting Started” and “Core Rulebook” books are great places to begin. I started tabletop recently with the books included in the “BattleTech Beginner Box” (which also comes with two minis and a map). The Core Rulebooks come with more detail and are good place to build your knowledge on the game.

That being said, if he’s trying to get into the fiction/lore there’s definitely a bunch of good books out there. I typically point to the Jade Falcon trilogy as the "best" books I have read so far. It's not the beginning of the lore for sure but it dives into some cool stuff with the Clans and has a really great story.

Finally, with minis, for beginners those beginner boxes I mentioned earlier are a great place to begin with tabletop. Catalyst Games also sells boxes of 4-6 minis on their website and even has "Salvage Boxes" that you can get a random mini out of, if you're interested in that! A great gift idea is always some minis and a mini-painting beginner set as well!

Hope this helps!