Is your client receiving both a taxable military pension, and nontaxable VA benefits?  That's possible these days, more so than it once was.  How much does he receive from both sources?  When did this change?  What is the date of the VA letter?  

"The Department of Veterans Affairs requires you to waive some section of your gross pension to receive disability compensation. This aspect means that if you receive $600 monthly, your retirement pay will reduce by an equivalent amount.

Concurrent Retirement and Disability Pay is an exemption of the VA waiver. This benefit type gradually restores your pension by eliminating the amount you relinquish. If you qualify for CRDP, VA will not deduct any amount from your pension apart from taxes. In addition, you will receive the untaxed disability compensation you are eligible for based on your rating."

https://www.disabledvets.com/resources/faqs/can-you-receive-va-disability-and-military-retirement-pa...