Smaller SFH = less maintenance , there are lots of single looking for a place to live .

He would need to find a place to live,which would take money off the table for collateral in his next deal.

Live way below your means and save the majority of your income.

Was it for a place to live for work before they found a permanent location or was it used for someone wanting to stay in the area as a 2nd home for the winter months?

China as a low cost producer is past- they have aged and standard of living out.  

My Ex-wife currently lives in my fathers home.

I wouldn't start investing in the US if you have no plans on coming back from living in China.

I recently purchased my first duplex in Peoria, AZ in September and I am using it as a house hack where I rent out one side and live in the other.

No, not places you heard people want to live, or were told, or think, no-no-no, where you KNOW people want to live. 

After 45 + years as a real estate investor, broker, lender, fund manager and syndicator, I’ve become aware that the “dream” of many investors and investor “hopefuls” is to be able to generate enough cash flow to live off their real estate holdings and accumulate enough wealth to make “work” optional.