Hello mgeth,
This is a great question, and congrats on the new employee! I can appreciate wanting to ensure simplicity for your employee by allowing them to use their existing login while also making sure that your account won't be negatively impacted. I'll point you in the right direction for getting some answers on this.
One of the great things about Intuit is being able to use one login across multiple Intuit programs, and typically they can be used for multiple connections across the same platform. It doesn't hurt to double check on this sort of thing however, and there may be some details we'll want to check on the back end to make sure the user can seamlessly transfer to your QuickBooks Time or if it'll be better to create a new one.
For that, please reach out to our dedicated QuickBooks Time team via phone or chat as listed here: Contact QuickBooks Time support. The article also lists support hours so you know when to reach them.
Have a great day!