Most claims of "Satanic cults" and "ritual abuse" have been proven false.
See official reports and research at [
www.culteducation.com]
Alleging family members were or are cult members/leaders is often a feature of such false claims.
Your friend should find a clinical psychologist or psychiatrist attached to a reputable clinic or hospital to discuss these claims with.
Keep in mind that some therapists have lost lawsuits and their license to practice for encouraging false memories in therapy that revolved around false claims about "Satanic cults" and/or "ritual abuse."
See [
www.culteducation.com]
It's likely that the above referenced research material may apply to your friend's situation.
This may be the reason you have so little meaningful information and are not having any luck researching the supposed group.