As others have said, the best thing your son can do is run far from this deal, buckle down, save his pennies (he probably already is doing this), house-hack, and improve a property with sweat, hard work, developing a DIY skillset, and self-managing tenants. 

.- Some lenders recognize NATO personnel and may include your Overseas Housing Allowance (OHA) as income.5.

The rental market is expected to stay flat or soft through 2025, then is estimated to start appreciating again once the new supply of multifamily housing reaches traditional occupancy levels.

Quote from @Charles J Sabo: This will be huge for house hackers out there. 95%LTV on 2-4 unit properties.

@Rolayne Taylor We are just alike I started in 2019 with my first house hack.

They will be an incredible resource for your first house hack and beyond in Phoenix and Maricopa County, AZ.

One is house hacking. 

We also have a house in Germany, but I do not think we can put that house in a trust.  

If the property is vacant, you will attract a larger pool of buyers as not everyone looking for a house wants to use it as a rental. 

. :)Writing a book on "How to entice your evicted tenant to leave for a weekend while you clean out the house and change the locks" is not teaching real estate.