Is my client seeing correctly that her son’s prior female friend is manipulating and controlling him psychically using satanic practices, to make him suffer now that he’s left her?

This indeed is the case. We understand your misgivings about this person because her stern affect has sounded an alarm bell for you but this is not the arrogance of delusional thinking by someone deranged, totally in the grip of their false thinking. She has had a long history now with this drama, and it has harmed all in her family, and she is picking up the threads and seeing that these consequences are a function of the manipulation ongoing for some time here. The woman in question, who is the perpetrator, is a dangerous person and has a pathological need to control the stable of men she views as her slaves carrying out a variety of duties or simply being puppets on a string she can control, and cause others to suffer who want their attention but will be denied because the man in question is being subjugated through psychic attack. This is wholly sinister, diabolical, and needs to be challenged and overturned in order for them all to get their lives back and have normalcy once again.