Can I add conditional contact form fields based on an API call?

Question

Given that we know the identity of the end user in our Web Widget contact form via the JWT auth pattern, is it possible to use this information to make an external request to our API to render an additional dropdown in the contact form? The ideal flow would be to use the user_id of the end user to hit an endpoint on our web server that fetches a list of patients for the user if the user is a healthcare provider in our system. And then if this list returns as non-null, we'd use it to render dropdown fields for a conditional custom form question like "For which patient are you making this request?"

Context

My company allows different types of users to submit support requests via our Web Widget contact form, such as patients and healthcare providers. When the provider is the submitter of the form, we'd like to collect more data about the patient on behalf of whom they are requesting (it's common that a provider submits a question on behalf of their patient).