This kind of brainwashing cult is so dangerous and the scum who perpetuate it are almost evil enough to convince me that there is some kind of god, just so that there is a hell for these sicophants to burn in eternity.
Preying on depressed people with low self esteem is so utterly wrong, and is pure expolitation. The kind manipulative control freaks, who poison vulnerable minds with their filth, are the kind of runty, unpersonable, ****wits who don't even get bullied at school because they are chickenshit beneath the bullies radar.
I have seen a similar group in action, the leader attemting to draw in fragile minds of people who were in no mental state to resist the sliming psycological manipulation of these freaks. It is disgusting and makes me so angry it is the only time I have ever struck someone not in self defense. The puny, whining, manipulative, combed-over, jumped up, self-inflated bullshit merchant deserved a followup kicking that I still owe him.
EDIT: I would strongly advise your friend to say no at all cost, and recommend that if his gf is already buying that sh*t, that he make her see professional qualified mental help.