It appears that he didn't move there permanently...so he file OR as a non-resident.
Thousands of College students work in other states during the summer....some adults take short-term jobs in other states for a couple months...but don't really move there...other than temporary housing, (or in an RV for some retired folks) . They all work in the other state as non-residents, until they more-or-less permanently move to that state
So his OR tax is as a non-resident (have work on that before NC)....then NC taxes everything from both of you, but NC will allow a tax credit for the taxes OR kept from whatever he had withheld in OR. (at least "up-to the tax NC would have charged on the same income). That NC credit effectively makes up for double-taxation.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
