I'm going to put my money on this one, tbh. I think Mum doesn't approve of him or her doing online (and/or in person SW), +/- other "lifestyle" things and he or she has gone no contact. Mum has subsequently gone for the nuclear option with not all the facts completely available to her.
Son or daughter has no moral or other qualms about what they're doing, is perfectly happy with their lifestyle and doesn't want to be dragged into all of this.
At least, I do hope that's the case because if not she's given a false affidavit, and since The Sun could still be in trouble here, I don't think that's going to go well for her.