While you preferred and accepted the answer provided by Mr. Adamo... that is a good example how sales people work - we are given only the good side of the product...
However there are other sides.
If the loan is used to purchase the home - that doesn't mean it is a mortgage. To qualify for the mortgage interest deduction
- the mortgage should be registered in the county where the property is located and the property should be used as collateral.
To deduct the mortgage interest paid to a person - the taxpayer should include that person tax identification on the schedule A - in case of a foreign person - that should be ITIN.
You might not aware - but the Mr. Adamo most likely does aware that mortgage interest received by a foreign person is taxable in the US for that foreign person.
If the US resident pays to a foreign person and that payment is taxable - the payer is treated as a withholding
agent and is required to withhold 30% of taxable payment.
So when you "buy" the idea of deducting the loan interest - you might like it, but when you know all circumstances - if doesn't have any financial benefits - and I doubt that you client will like it.