As far as filling out a question on a form, we would need to see the question. He does not have to provide his state of residence, though sometimes when people draft POAs they do just to help to identify the person (e.g., John Doe of Anytown). In the same vein, the document may identify your residence to help identify you.
The jurat for the notary would be for the State and County in which the notary is commissioned.
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