1- Yes you are right. Don’t overburden him. Let him learn the details step by step.
2- Have him watch this prayer video (you should teach him the Shia way):
https://youtu.be/wQd0oEvSmdY
3- A month later have him watch this series:
https://youtube.com/playlist?list=PLfzkUHqQSNMZphZWco7rrjdrIhOX7HVj6
4- Later have him read this book:
https://www.al-islam.org/inquiries-about-shia-islam-sayyid-moustafa-al-qazwini