I accepted a tenant into a B class rental a few years back who was making low 6 figures at the time as a union boiler-maker but had NO CREDIT SCORE!

So assuming your son has low debt, then he should be able to qualify for a house in the low $300K range. 

There are a lot of hotels right now that are failing and going under due to low cash flow -so its a failing hotel.

The only caveat with that loan is that you'll need to purchase in a low to moderate-income tract. 

If you are very conservative purchase a fixer upper so you can force equity and hopefully have a low enough payment so that you can LTR the property or even sell for profit should the STR avenue not work. 

I own a 200 year old house that has a very low cost of repairs and maintenance over the 4 years I've owned it.

I haven't filed a claim all these years but insurance is for the what-if and to be used for the high-ticker items, but chances of damages exceeding the 5% is low.  

Once complete, refinance into a low or no seasoning DSCR loan.

I made a low offer and it was accepted.

Some of it is luck or taking advantage of opportunities (eg low interest rates).