I know for a fact that you can use unused, nonexpiry Walt Disney World passes at
Disneyland. We did this last summer. The key, of course, is that there are days left on the passes and that the passes are nonexpiry. You have to do this at the turnstile--the CM takes the pass to a computer where he checks that there are days left and then removes a day. It's a bit time-consuming (and you lose a bit of money in the exchange, as DL costs less than WDW). But it worked for our family.
However, given the kind of luck Ed had on this trip, I have a sinking suspicion that he does NOT have nonexpiry tickets.