What version of JFBConnect are you using, and do you know the name your boss subscribed under? Priority support is for active subscribers only.
As for your question, it can be configured to automatically link users if their email is in the system, or it can be configured to force the user to link their accounts. Let us know what version of the CB profile plugin, JFBConnect, and Community Builder you're using, along with how you want it to work, and we can help you configure it that way.
Thanks,
Alex