Maybe you will get your mom started to think a little about it. Different groups define "cult" in different ways, but the one that got me thinking is this one... (copied straight out of wikipedia, I'm sure there is better info out there on this definition)
Definition by secular cult opposition
Secular cult opponents define a "cult" as a religious or non-religious group that tends to manipulate, exploit, and control its members. Here two definitions by Michael Langone and Louis Jolyon West, scholars who are widely recognized among the secular cult opposition:
Cults are groups that often exploit members psychologically and/or financially, typically by making members comply with leadership's demands through certain types of psychological manipulation, popularly called mind control, and through the inculcation of deep-seated anxious dependency on the group and its leaders.
"A cult is a group or movement exhibiting a great or excessive devotion or dedication to some person, idea or thing and employing unethically manipulative techniques of persuasion and control (e.g. isolation from former friends and family, debilitation, use of special methods to heighten suggestibility and subservience, powerful group pressures, information management, suspension of individuality or critical judgement, promotion of total dependency on the group and fear of [consequences of] leaving it, etc) designed to advance the goals of the group's leaders to the actual or possible detriment of members, their families, or the community."
The common anti-cult definition summarised,
Manipulative and authoritarian mind control over members
Communal and totalistic in their organisation
Aggressive in proselytizing
Systematic program of indoctrination
New membership of cults by middle class