It would probably be worth the effort of trying to modify your reservations in order to use your nephew's TS credits. If one person pays out of pocket for the least expensive one credit TS meal, you'll have 4 TS credits to use at a signature restaurant. Or add another TS meal at a one credit restaurant to use at least two of the credits.
At the very least it would be better to use any leftover TS credits at CS or for take home snacks rather than leave them unused.