This is pretty clearly a chain-email written months ago by a McCain supporter, breathlessly warning of the dangers of electing an Obama administration.
The "...this is the type of change you can keep" is a dead giveaway.
That explains why the author is not known, and why the whole point is that you will get fired if taxes increase.
I don't find that threat credible. If the guy wants to retire, he will sell his company, not shut it down. Even if it's unprofitable, he might still find a buyer who hopes to turn it around, or values a part of it. This often comes with layoffs, but firing every single employee would probably be stupid.