It appears his pay is taxable. The following is taken from the Pennsylvania website:
"Is military pay taxable for PA personal
income tax purposes?
Military pay (including compensation for weekend
drills) earned within and outside Pennsylvania by
PA residents is subject to PA personal income tax
as compensation.
Income received by a PA resident for all military
service performed inside Pennsylvania – even if
on federal active duty or federal active duty for
training – is fully taxable, unless for active military
duty within PA for an emergency pursuant to 35
PA C.S. Ch. 76."
For additional information - click on this link: PA
- Military Pay
