I'm surprised he did not like the Navigator. While I did not like the most recent version with almite scales w/slots, I loved the G-10 ones.
Skip the Jester. Its a great little peice but probably too small as a "pocketknife." Its quite small.
Go with the Kiwi or SS Cricket. If he's a lefty, definately go with the Kiwi. The framelock on the Cricket is designed for righties.
The Kiwi is a bit more refined. The jigged bone Kiwi is a bit more refined still. He would be very pleased with it, I'm certain.
Both the Kiwi and Cricket are very ergonomic when open, but a bit harder to open for big hands. Of course that just comes with their small size. The Cricket seems to "spydie-drop" better. Maybe because the thumb-hole is a bit larger on the Cricket.
The reverse "s" blade on the Cricket is less conservative than the almost wharncliffe style of the Kiwi.
I really like both. I've given both as gifts. Kinda depends on the specific situation.