Odd story. The point at which you're selling your stake for $100, you've basically decided to give it away. Which raises the question: if he was just going to get $100 and nothing more, why not just hang on to it?
Hanging onto stock from a company I co-founded a few years ago has caused me tons of stress because that company constantly files for tax extensions forcing me to do so as well. I have other financial processes which rely upon timely processing of my completed tax filing, and every year it causes me trouble. So if something is thought to be worthless and about to fold, "just hang onto it" could cause a non-zero amoun…
If you're just holding shares/options in a corporation that isn't going through ownership changes, that problem doesn't exist.
That said, there are still valid reasons to cut ties with past partners/employers.