Send me your address and I'll send a couple out to you. :)
I assume he's using the tactical tailcap (forward clicky with protruding boot). If so, you can take the guts out of it and put them in the regular tailcap (which is a tail-standing design). You'll then have a forward clicky and the button will be recessed, lessening its chance of being detached again. Of course he'll have to see if this configuration is easy to actuate for him... some people can't get the tip of their thumb onto the boot too easily, something you wouldn't want in a tactical situation. Works fine for me though, so he'll just have to check.
Here's an excerpt from an instruction sheet I wrote for the Tiablo tailcaps:
Tiablo A9 tailcap switch boot swap
To change out the tailcap boot, use a pair of sharp-pointed tweezers or small needle-nose pliers to remove the switch assembly retaining ring inside the tailcap. The retaining ring has two small holes in it, insert the tweezers/pliers into these holes and unscrew the ring counterclockwise. There may be two of these thin rings to remove, depending on the style of tailcap. After the ring/s are removed, you'll see two slots in the switch module. Use the tweezers/pliers in these slots to remove the switch assembly in the same fashion as the retaining rings. You'll then be able to remove and replace the switch boot. Reinstall everything and you should be good to go.
