1. Try to call DL and cancel the tickets to get DL voucher. Zero chances to get $ unless it was a full fare ticket, or it was a schedule change.

2. (1) may not work - some tickets could be cancelled only by Expedia... DL agent will tell to call them. In this case your friend will pay also expedia cancellation fees, but may get expedia voucher (non-restricted to DL).

3. I would wait for schedule change... and than call DL or Expedia to get $$.