PA and new York State tax - WFH

My son worked from home in PA for a NYC based company during last summer internship. Never went to NYC office or lived there. I think he would be considered non-resident for NY.  His employer withheld NY state tax in his W2. Please advise how I should file state taxes for PA and NY.

 

Can I file NY state tax with zero wages and pay PA state on 100% wages to keep it simple