Generally, Veterans Disability benefits are not taxable (and therefore not reportable) on a tax return.
See Do I Need To Report My Veteran Disability Payments?
If you have enough taxable income to file a return, you should file jointly even if your spouse has no taxable income.
Married Filing Joint generally yields a better tax result than Married Filing Separate even if one spouse earns little or no taxable income
Generally, filing jointly will give you a bigger refund or less taxes due. When you file separately, your tax rate is higher and you won't be able to claim a number of deductions and credits:
See Do I Need To File a Federal Tax Return This Year?