I shared my cameras to a friend but he can not access playback and can only watch live. How can I make him have access to playback to check things when I am unable to.
You can’t. A recipient of a share is limited on what they can do. There is a wishlist to allow more control of what a share recipient can and can not do.
The only other solution is to have your friend log in with your account (not likely what you want to do).
Give it a vote!