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.
People who are going to prison know it in advance. They may be transferred from a jail, taken to prison from court after a conviction, or report to prison on a date set by the court. People released from prison may be released to parole supervision or to some other type of community program.