Does he understand, Deeds, Due On Sale, Insurance, tax implications, servicing, contracts and so on?

Technically it would be best to get a C Corporate or S Corp. to flip properties and since you are considered a dealer if you do several properties a year and this could have negative tax consequences in an LLC.

There are also additional costs of operating and maintaining an LLC, like separate bank accounts, annual report filings, tax filings, etc.2.

Keep in mind taxes go up as do rents.

After collecting tenant pass-throughs for the year, do you pay the property taxes at the end of the year or the beginning of the next year?

Find out if they owe any back taxes.

An other advantage of paying with credit card may be that you will not have to send the provider a 1098 tax form (only an issue if the total yearly amount is over $800). 

.: The applicant needs a social security number or an individual tax ID number (ITIN).

As more people placed more properties in STR inventory, and as more municipalities taxed and regulated the industry, the profitability of the overall industry has reverted to a much more aligned (lower) risk adjusted return.  

If you didn't receive any income but you had legitimate business expenses, you should still file a Schedule C to deduct those expenses.