My son wants to get his private pilot license and it has been along time since I did mine. Are people still using Jeppessen books? What would be the best way for him to get his ground portion done?

Sealy,

There is a wealth of information available to a student today. Some excellent video presentations cover much of the material, and various companies produce student packets with books; electronic versions are available, too, and multiple test services offer preparation that guarantees passing the "written" (which ceased to be a written, long ago).

Most flight schools offer in-person groundschools and training. Given the quality of graphics and the ability to review a lesson as often as one wants, I'd pick any of the courses today and start there. Sporty's, for example, offers a fully private pilot video course that will cover everything one needs to know for the knowledge exam ("written") and the material needed to get through the private.

I also recommend joining the aircraft owners and pilots association; they have two excellent magazines, one of which is geared toward students (Flight Training magazine).

All manuals available for FREE download

https://www.faa.gov/pilots

Before you start spending money

I did king ground school. It definitely got the job done, I got a 92% on my knowledge exam, but if I was to do it again I think I might check out Sportys.

I did the Sporty's ground school a few years ago. The videos are excellent and I preferred their style over King's. The test prep was also very good and helped me score 100% on the written. Used them for Instrument as well.
Cheers...