I would not say it is impossible, but more or less, you have to wait until the re-evaluation is scheduled. That is the purpose of TDRL to see what the paasage of time does to let the member heal or stabilize (or in some instances, to get worse and receive a better rating). As far as where his case is processed, he will get an examination somewhere in the area of Arizona (given that there are military bases and VA facilities, it will likely be near to you). Where they process his case is something that is up to them. You might ask if he can be processed through Ft. Sam in San Antonio.
Hope all goes well!
Hope all goes well!