hypothetically, if the story about a mother joking about offering her 13 year old son lubricant so he could jerk off more effectively (because she can tell when he's jerking off) were true...IN YOUR OPINION, would it warrant concern on a moral or legal basis?
In my opinion, no.
Unless the woman is actually approaching the kid while he's masturbating and literally putting the lube on herself, it's not child abuse.
The woman is guilty of nothing more than making a mildly offensive joke on an internet forum.
You do that all the time, dumb dumb.