Hi @mgb, Mayo Clinic medical teams work as a group. It is more likely that your husband's records will be reviewed by a team of experts. You can read more in the answers to frequently asked questions here: https://www.mayoclinic.org/appointments/faq
It states:

Q: Can I request a particular provider?
A: You may wonder if it's possible to see a specialist you have read about. Or someone who has been recommended by a friend or colleague. Mayo Clinic can't honor all requests, but we try to when possible. However, we won't grant requests for care team members based on race, religion, ethnicity, gender, sexual orientation, gender identity, language, disability status, age or any other personal attribute. We strive to create an environment where everyone in our diverse community feels safe and welcome and is treated with respect and dignity. Appointment specialists are specially trained to match you with the provider or group that's the best fit for your diagnosis and your history.

Here is the link to request an second opinion review: http://mayocl.in/1mtmR63