You mean they had multiple "virus" or antivirus? do confirm.
Also, please go ahead and run a complete anti-virus scan on your device using the safe mode, here's how to access it: Click here, if the issue persists on the safe mode as well, you may want to perform a power reset using the steps mentioned here,
If nothing works, the device could have been compromised by spyware, I suggest you perform a system reset using the steps mentioned in this link: Click here.
Let me know how that pans out,
If you feel I was helpful, simply click on Accept as Solution to help the community grow,
That said, I will have someone follow-up on this to ensure you've been helped,
Just in case you don't get back to us within 24 - 48hrs, and have a good day, ahead.