A month post closing, the son of the buyer (mother) has written a "legal" request to have us buy him a new refrigerator.  

This means you can sell, lease, or pass on the property as you see fit, just like any other property owner.Full Ownership RightsYou have the same rights as a Mexican property owner, including the ability to sell, lease, transfer, or mortgage the propertyLegal SecurityThe Bank Trust is a well-established legal mechanism in Mexico, ensuring your investment is secure and protected under Mexican law.Renewable TermsThe trust is set up for 50 years and can be renewed indefinitely, allowing you and future generations to maintain control over the property.Estate PlanningThe trust makes it easier to pass the property on to heirs, simplifying the inheritance process and reducing potential legal complications.Although the process might initially seem complex, it is entirely managed and supervised by a reputable banking entity.

Now they want to put the properties into RE Gain Fund, LLC UpREIT (which appears to have been established in 2023). 

Right now, homeowners across the country are seeing record amounts of equity.According to Intercontinental Exchange (ICE), the average homeowner with a mortgage has $319,000 in home equity.Why Have Homeowners Gained So Much Equity?

.: Is it legal, per the IRS, to rent my primary home back to myself? 

Your client should consult a real estate attorney to draft an agreement with the ex and ensure there are no legal or tax issues, especially since this is an investment property.

So, to try to go a legal route because they might have fixed something a little over the limit isn't going to work.You will have to face that you selected someone that was not the right fit and be more hands on. 

Additionally, your brother would inherit your cost basis in the property, which could result in significant capital gains tax if he sells the property later.

It is my understanding that the new owner will have the house at the cost basis of my purchase price, for calculating capital gains taxes or depreciation.For gift tax purposes for you - FMV.For capital gain tax purposes for the recipient - your original basis/purchase price 

To legalize a curb cut in NYC, your first step is to hire a licensed architect or engineer.