About Taxes in US?

Is this property something he had part ownership of? Or was the property owned by you or other family members who are just deciding how to divide the money up to those you are giving it to? Because the second one is a gift, and gifts are never taxable in the US to the party that receives the gift. The amount of money you are talking about would have to be reported by you on a gift tax return, IF you were a US citizen. You would not have to do this.

But, if he had some ownership in the property, then the money he is getting is a return on his investment, it's not a gift. We could not tell you how much tax he would owe, if any, without also knowing how much profit he realized on that investment and what other earned income he has and what state he lives in and what his tax filing status is. It can get very complicated, so if this money is not a family gift to him, he needs professional tax advice.

what your son inherits is not taxable in the US

Many states only charge after $14k so tax on $500 isn't much but, that is on gifts. Considering that it is an inheritance, I don't think he will have to pay taxes on it at all.

How much is paid by him? None. If there is tax to be paid, then you pay it. The law in the U.S. is that the tax on gifts must be paid by the person who gave the gift. But if it's only 14,500, then there is little or no tax anyway. If you want to be on the safe side, send half in December and half in January, so that the amount in each year is under $8,000.

It is not a taxable event. If there is a foreign bank account involved he may have to file a FBAR report.

Your son will pay no tax on the gift. Gifts are never taxable to the recipient but to the donor. However if you are not a US citizen or resident yourself, you cannot be compelled to file a US Gift Tax return. Nobody needs to report anything.

There is an information return required for gifts in excess of $100,000 but that obviously does not apply here.

He pays nothing. Gifts are not taxed as income to the recipient.

depends on where he lives and how much he makes during the year in his job...

without knowing all his financial info and his location its impossible to help