Anne,
This is the right spot to bring this type of question and concern. Per our meeting guidelines, attending a virtual meeting where others cannot be overheard is an important part of maintaining privacy, anonymity, and confidentiality. Your inclination to express that in a Christian manner is spot on and I know the balance is a bit delicate. For the well-being of the group and each participant, it is important that someone say something.
You could send him a private chat message to ask him to attend in a place where others cannot overhear or oversee the meeting, adding that it’s an important part of protecting the privacy of each attendee. If that is not effective, bring it up to the meeting facilitator and suggest a group announcement while they’re in attendance. You might mention to the facilitator before the meeting that you’re going to request that he find another place to attend the meeting so he/she is aware. If they are still not in compliance with the guidelines, then further action might be required such as removing him from the meeting in order to protect privacy and anonymity, which is paramount for wellness of the group. I believe this is aligned with what Jesus would suggest (Matthew 18:15-20).
Feel free to report back here or inquire more about what can be done. Thank you for bringing this to our attention!
Scott