My clients get all sorts of weird referrals pins/needles, feelings of release elsewhere in the body, sometimes impared feeling/sensations, releasing scalenes and pect minor can be very interesting indeed as far as arm hand sensations are concerned.
I tend to find with neck issues, scalenes are nearly always involved, short in other words. I know a lot of people overlook them and trigger sub occipitals and the other posterior muscles which allow the scalenes to shorten even more sometimes having a greater impact on odd sensations.
I had really short scalenes a few years ago, that used give me numb patch in my thumb.
I treated a guy diagnosed by a doctor with a torn pect. It was scalene impingement. No chest pain at all within 10 mins of treatment, didn't even work on the pect. Interesting game.
Sensation came back though, so your friend has nothing to worry about. Mind you, I've come across people who don't know how to differentiate between a trigger and stuffing their fingers into a nerve tract.
HTH.
Kevin