Hello Jean! Thank you for your question. I will be assisting you today.I'm sorry about the issue. You can only transfer books if you register his kindle to the same Amazon account / email address as on your kindle. On his kindle, go to menu/setting, and deregister, then register with the same email address as on your kindle.Please let me know if you need help with that. Thank you,
If you need still need help later, please let me know any time. Thank you very much.