I read the post but didn’t understand why they had to walk. Why did they not get their $800k back?
Supporting the founder (and earning goodwill for it) is probably worth a lot more.
I'm guessing it's more that the buyer was only prepared to go to 4mil, and the _seller_ had run their numbers and came to the conclusion "4mil minus that $800k isn't enough to secure my families future, and I'd need to walk away from the deal unless they agree to forgive that $800k" so he asked them, and they agreed.