Military disability pay is not paid by DFAS. It's paid by the Veteran's Administration (VA). Disability pay from the VA is not taxable or reportable on any tax return. That's why the VA does not send a tax reporting document of any kind. At best, the recipient of disability pay from the VA will receive a letter once a year outlining the benefit and any changes to the benefit that may have occured, or will be occuring in the near future. It's also likely included with that letter or mailed separately from it, would be a 1095-A, 1095-B or 1095-C outlining the period of healthcare coverage that applies to the service connected disability.
In a case where one retired in the current tax filing year and they are awaiting evaluation/approval from the VA, DFAS will pay the entire amount of retirement due until such time the disability benefit kicks in. Once the benefit kicks in, the retirement pay from DFAS will (usually) be reduced by the amount of the disability pay. If the disability is retroactive to the date of retirement, then you get a refund for the taxes withheld by DFAS prior to the retroactive disability being approved. For some, this can be quite a large amount. Just follow the guidance at https://www.irs.gov/individuals/military/special-tax-considerations-for-veterans and follow that guidance "TO" "THE" "LETTER" of perfection. Having been military, you should already know how picky they can be with it comes to following directions. Do no more, and no less than instructed.
