In the document at
https://info.wolflair.com/xwiki/bin/...rsus%20Control it says that the PC must be "owned" by the person with the Patron account.
The Apprentice account should be given "Control" of the PC by the "Owner".
dndbeyond is much simpler for D&D 5th edition. The PC simply needs to be in a campaign for it to gain the sharing benefits. On their system there is no need for the user to differentiate between controller and owner for PCs (it is all hidden behind the scenes).