There is no rule that exempts vets with a 100% disability from filing a tax return. Never has been either. But as I'm sure you already know, all disability pay you receive from the VA is not taxable or reportable on any tax return. Not ever. So if disability pay is your only source of income for the entire year, then you don't need to file a tax return at all.
But if you receive any income during the year from other sources, then depending on the type of income as well as the amount of that income, you could be required to file a tax return. But even then, you would not include your VA disability pay on that return.
