So, let's get back to your question...
Are you looking for a powered or manual system?
How much money, ballpark?
How much effort will the individual put into it...or will it just end up collecting dust?
An inexpensive powered setup that is popular around these parts is the Work Sharp. Those who like it seem very satisfied. (I've never seen one in person.)
Manual systems can be as basic as the Spyderco Sharpmaker, Lansky, GATCO, DMT Aligner...or...
...as involved as Edge Pro, KME, Hapstone, Wicked Edge and other guided systems.
We kind of have to have some parameters to work with, understanding that there is no "best" per se.
But, perhaps we can narrow it down if we know the types of knives, steels, condition etc. Will they require being overhauled or just a touch-up?