Hi,

I am transferring $90,000 to the US to my brother and I wanted to know does he need to declare this as part of his yearly savings / tax returns (I'm aware that I do not need to complete form 3250)

Do I need to provide a copy of where this $90,000 came from?

I'm trying to understand the tax system in the US before I transfer to my brother

What evidence would I need to provide when he does his tax returns on the $90K

Assuming the $90K is a gift or a transfer of his share of an inheritance, he needs to report NOTHING on ANY tax return he may submit.

Gifts are not taxable to the recipient, nor is an inheritance (UNLESS he lives in a state with an inheritance tax).