I'm a big fan of uke books so pretty much have every one i've found so far with a few exceptions...looks like 25 or so. I can give you a few recommendations based on what i like but it depends on what kind of stuff your dad wants to play.
There are a ton of jumpin Jim books and they seem pretty fun for sing along type stuff. I have a few of them and i think the movie one is probably my favorite. They're pretty good for learning the basic chords and stuff since they are generally pretty simple and give familiar material to strum along to.
If your dad likes older tunes then I'd recommend
Cat's Meow which is like a songbook full of tunes from the twenties. I'm not familiar with a ton of the songs but it comes with a CD to help with that. It uses some more advanced chords but has fingering diagrams over the songs so it's probably good once he wants to learn some more unusual chord shapes.
Beatles for Ukulele is another songbook with chords for a bunch of Beatles songs. Again most of these aren't beginner songs as they use some weird chords too.
I just recently got
Exploring the Ukulele which some other folks have mentioned. It's probably one of my favorite books so far that focuses more on fundamentals than song arrangements.
I'm not a huge fan of pure theory uke books as a lot of it tends to go over my head. I prefer learning the theory as i learn how to play songs. But for pure theory i was able to follow the Chord Progression ebook at
How To Play Ukulele more than most. Of course ebooks might defeat the appeal of actual books.
For totally new players Jumpin Jim books will probably be the most accessible to just strum along with.
I didn't get into fingerpicking until i'd been playing for a few months but if you want to hear about books with fingerpicking tab then let me know and i can give another blurb on my favs. Or if you have questions about a specific book just ask as i probably have it.
Chris
