Whenever I read Matthiessen the naturalist, I am reminded of a film clip I once saw of him trying to catch a snake in the wild.
This webpage only addresses apportionment of incarcerated veterans' benefits, which is the VA's process of taking all or some of a veteran's benefits that would otherwise be reduced or suspended due to incarceration and instead paying those benefits to the veteran's eligible dependents based on their demonstrated financial need.
If, however, the claim is not submitted until after this 1-year mark, then the veteran will lose all the pay for the period between his date of separation and the VA Disability Rating Decision, and he will need to provide evidence that his claimed conditions were definitely service-connected.