Your son, as an active duty member, can keep his state of legal residence (SLR) – usually his home of record state. Therefore he would be still considered a resident of Connecticut unless he decides to change it. To change the SLR, a DD Form 2058 must be submitted to the local finance officer and accepted.
He might qualify to have his military pay excluded from Connecticut income tax if he meets the requirements, please see Connecticut Income Tax Information for Military Personnel for more details.
His military pay will not be taxable in North Carolina (the state he is stationed in) and he won't be required to file a North Carolina tax return if his military pay is his only income.
