No, there is not (or there shouldn't be). Factory Reset Protection uses a protected storage area that can't be wiped without special privileges or initiating a Factory Reset from Settings. If the user was able to root the device they could manually launch Settings via adb and do the reset themselves, but rooting is typically not possible when you can't even get past the initial setup wizard.
If he sends the phone back to you: log in with your Google account at the prompt in the Setup Wizard, finish the wizard, and then go to Settings and do the Factory Reset from there (rather than via recovery, etc.).
See this Android Police post for more details on the feature: What Is Android 5.1's Anti-Theft "Device Protection" Feature And How Do I Use It?