Taxpayer home state was NY when entered military, no longer a NYS domicile. W-2 shows NY and taxes withheld. How to exempt military pay from NYS.
You can consider him a nonresident if he meets the exceptions. See NY pub 361
I know that, problem is I get an error when I try to allocate,
If you are filing him as a nonresident did you fill out section at bottom of federal info sheet part XI. I haven't done one this year, but last year I had no issues
