If they were not prepared to hold for cash flow when their equity "took a hike", or not able to adjust their positions, they lost big.Bottom line is this.  

However, after thinking about it, I would much rather sell it because I'm not able to get the rental amounts I originally thought and I would much rather buy 2 duplexes so I have less of a headache.

I am not able to assist in this instance, but want to wish you good luck in sorting this situation.

For example, the bank may wait until January to pay the local tax bill, and you are not able to deduct it on taxes until it is paid out of escrow.

Your development in RE is certainly notable.  

Generally, any property 4 units or fewer is going to be valued based on square footage, but there are diminishing returns the larger a house gets (with a few exceptions- notably, super high end properties).For example- there is a corporate mega builder in my market and they build out subdivisions of hundreds of homes at a time.

Second, are you not able to negotiate for a 3-4 day work week at first?

He is not able to leave the house with any ease.

Because of my industry, I am not able to invest in ANY individual stocks and therefore only have a few options open to me: real estate, ETF’s, mutual funds, bonds and private investments in private companies.

I could be wrong but thinking for a minute here and I'm not able to come up with a licensed profession that has been completely replaced by the internet or some other technology.