I honestly believe herbs can repair almost anything. I have this gut feeling about it.
Now I get that that's not much to go on, but I'll tell you this: every medical problem I've
ever had, when I had no hope for recovery...along came some plant or another to save me.
Plants make a big difference to our health. Now, as with anything, one must be patient and take much dosages to achieve an effect. It's not for everyone because of this. Some want quick fix results, and herbs are more appropriate for slower-acting but long term health maintanence. So now for your colleague, from what I've read and tried, I'd say St. Johns wort is useful for peripheral nerve repair, while gotu kola and holy basil (tulsi) is great for brain and body nerve protection. Tumeric is highly effective for reducing inflammation which may be hindering the nerve. These taken in combination, over long term will hopefully help your friend heal.
All the best