[curun1r]

> My hypothesis of what is happening is that when you're resting your arms on the table, you are preventing the free flow of blood in your forearms to your hands.

If this is what's happening, perhaps taking up indoor rock climbing would help. I know of no better exercise for improving the body's ability to send blood to the forearms and hands than rock climbing since so much of it depends on grip strength. Failing that, there are grip strength training devices (example...not suggesting this particular one: https://www.amazon.com/dp/B00HB7V6KS) that he might keep by his desk to use when he starts getting cold fingers.