javascript - Braintree/Javascript: How do I get access to previous customer's billing address?

Question

I am trying to load previous customers' billing info (address) into editable fields on their account page. I am using the Javascript v3 client implementation of braintree and use their Drop-in UI . I am making a call to a server on the backend (backend team is separate from my company) of our app sending them the user email and the response has a clientToken that I take and use to create the Braintree instance.
Where is this customer billing info available that I can use to populate these fields? Is it in a payload that client can consume or is there work that the backend needs to take care of this.