No, I believe the Rewards Redemption Card is tied directly to the credit card account. You can transfer the points to your own redemption card and probably let your nephew use it, but it remains tied to your account.
Judy’s right, the only Redemption Cards you can transfer money to are the ones you’ve ordered under your account. But you can have multiple redemption cards.
So just order a new card, load with points, and give that one to your nephew!