Yes, glues have come a long way in all that time. There are three basic kinds (and I'm going to ignore the two part epoxies!): Liquid, Tube and CA (Cyanoacrylate AKA Krazy Glue).
Liquid: Best all round glue. I use Tamiya Extra Thin mostly, and have a bottle of their "regular" kind which I call Thick. I also have a bottle of Testors Liquid. All come with brushes for applicators. The Testors and the Extra Thin work by capillary action, and so are best for attaching longer pieces like airplane fuselages or ships. Place the pieces together, insert a razor blade to hold the gap open and touch the brush loaded with glue. Observe how the glue runs down the gap, them press together. It dries, or flashes off, very quickly and works by melting the pieces together. Properly applied and sanded, you won't be able to tell where the seam was. The capillary action also works with hands, and I don't think one of us hasn't glued together a fuselage, only to find a perfectly etched fingerprint melted into the most visible part!
Tube: Still a standby, but most of us don't use it anymore. I keep a tube of the orange Testors around as I find it good to attach small pieces that requires good initial "tack" or "grab". Mostly it stays in the drawer though. The Tamiya Regular I mentioned above is almost as good, and is easier to work with. I find that tube glue is much like melted mozzerella cheese on a pizza, stringy and tough to deal with!
CA: This glue isn't just Krazy Glue anymore! There are numerous brands, and three basic "weights": Thin, Medium and Thick. It can be used for gluing together disimilar items (brass to plastic, for exampel), and can also be used to fill gaps. In fact, the brand I buy is Zap-A-Gap brand. Be careful though, fully cured CA glue is very difficult to sand. This glue also comes with the typical CA characteristic of being able to glue your hand to whatever you touch, so be careful! Acetone based nail polish remover helps a little. CA glues dries by chemical reaction, and you can also buy accelerators which makes the bonding instant and permament!
Good luck with your son. I came back to the hobby the same way, and got hooked, while my son built a few and moved on to other things. ![Sigh [sigh]](/emoticons/icon_smile_sigh.gif)