Getting pop ups saying iPhone has viruses

If the popups are coming from the calendar app, try this: Delete spam calendars and events on iPhone - Apple Support

Or if they are appearing in Safari: Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch - Apple Support

This is a public forum; anyone on the Internet can read what you post, even if they don’t have an Apple account. That’s about 6 billion people. So it’s not a good place to post any personal information such as a phone number. I’ve asked the hosts to mask it.

His phone does not have a virus; see→Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

Try deleting your Safari Cookies and History.

https://support.apple.com/en-us/HT201265