Even without this script, if you browse to a folder where you have stored an instrument and press enter on the nki file, it will load in kontakt and you can play it. The parameters would be inaccessible though, but I can at least play the sound.
Does your friend use a Komplete Kontrol keyboard? if so, it would still require sighted assistance, but often the parameters of an instrument you can right click and choose ‘learn’ then he can move one of the knobs on his controller and that parameter will then be mapped to that knob. I suppose this would work on any controller keyboard with assignable knobs or sliders.
Finally, within Komplete Kontrol program, if you have a Komplete keyboard, you can go to the midi tab and assign the soft buttons or knobs to midi CC numbers. If the instrument uses standard CC messages for any of its controls, then you can press the Midi button on the keyboard, and the knobs and buttons will send out the midi Cc.
These are the partial solutions I’ve discovered so far. Kontakt accessibility is certainly an issue, and some products simply aren’t going to be friendly enough to warrant purchase for a blind person.