Is it ethical to share names and emails of survey participants?
Your friend can seek retroactive permission from the participants. They can email all of the participants to ask them for permission to disclose their contact details with the friend's advisor for the purpose of validating the survey. They should probably also ask them to complete a consent form of some kind, the details of which your friend should discuss with their advisor. Without seeking permission, it would be unethical. Depending on what the survey is about, the participants may not want their details being shared with your friend's advisor.