Reddit reviews Kitplanes

Personally, I'd highly recommend Kit Airplane Construction by Wanttaja. He does a great job of explaining the various tools and skills required to build the various types of aircraft (composite, wood, metal) along with best practices for all of them. It's a great book to help your dad figure out what kind of plane he'd like to build and what he's getting himself into if he does decide to build. A subscription to Kitplanes magazine would go a long ways too :-)