Hi Sherrie, you are the profile manager so you can detach the mother, you have added the source to show her name was Mary. You know her name was Mary but you do not have a lnab for her right now. His father has two wives and one is Mary Unknown. You can attach her as his mother since it appears that she is.
That profile doesn't fall under the guidelines for PPP. It would also have to be protected by a project. This page explains more about the reasons for adding Project Protection (PPP).