If I was dictator, the punishment for double-dipping would be to put the convicted to a state of "zero dip" -- no pilot certificates (revoked, not suspended, do not pass go), VA cash clawed back, a fine in the amount of their total ill-gotten pilot earnings.
I agree that "VA Disability" seems like yet another governmental santa claus situation, over-used, abused, under-administered -- and has nothing to do with medical fitness to hold a first class medical. Fine. Change the medical regs then. Or carve out an FAA loophole that allows a diagnosis of "flight compatible PTSD -- dude can fly a plane fine, but he wets his bed at night now and he needs a perpetually replenishing loaf of taxpayer cash to make it all better" and whatever test standards that may support. Until then, these dudes should burn. And I have no confidence that they will.