Purple color under all the Nails

You would need to identify the root cause of the discoloration. The most common cause in TMC would be due to liver blood stagnation. Also start by ruling out lifestyle factors like working with dyes or wearing tight gloves for long periods of time etc. What other signs and symptoms is he experiencing?

Acupuncture just does not work like that. You rarely if ever design a treatment based on a single symptom. Purple coloration under the nails, for example, could be bronchitis, moderate or even severe cardiovascular issues such as coronary artery disease, autoimmune conditions such as raynaud’s, etc.

Even with the underlying factor decided upon in western terms you wouldn’t base a treatment just on that either. That’s where Chinese Medicine diagnostics becomes critical - you should look over what does acupuncture treat? and how designing an acupuncture protocol to better understand on a basic level how acupuncture is utilized.

There is rarely, if ever, a symptom like this without a cause - your skill as a practitioner is, ideally, to fix this cause without it ever getting to the point where it is experienced in it’s fullest manifestations by the patient (somewhat generally, before the point that the patient is ill enough that western medicine provides a clear diagnosis).