I Have Used My Actron OBD II Pocket Scan Code Reader For About 2 Years Now
My wife gave it to me (was on a sale for $50 at Advance).
It works great! The latest model of these is available at autoparts stores like Advance for about $70. It will read codes, erase codes, and comes with a little book for looking up and translating them. I believe it is made by the same folks that make the one that Tester referred you to. That one for $213 is a code scanner, not just a code reader, which gives more information.
I guess it depends on how often hubby is a “mechanic” (pretty regular or occasional), how much you want to spend, and how elaborate you want it to be.
Example: My wife came home with the “check engine” light “on” Thursday. I read a code PO133 with the Pocket Scan. That translated to an oxygen sensor, Bank 1, Sensor 1 (location of sensor, since there are 4 oxygen sensors). I replaced that sensor and turned off the “check engine” light.
Tester has given good advice. Your husband would be happy with that scanner. If you are on a tighter budget, he would be happy with the Pocket Scan Reader.
By the way, some sort of a service manual (specific to a particular car make, model) would go along nicely, if he doesn’t have one.