Rockstar wrote:

Mom should have put a stop to this behavior back when the kid was two, but Mom didn't want to put in the work/believed her precious angel would be scarred forever by the word "NO"/whatever bullshit reason Mom came up with for not parenting her child, and now she has to deal with a holy terror.

There is no evidence for any of this. If, as you claim, the mother lacks backbone and the child is a "holy terror" then she would be holly terror for everyone, including teachers and camp counselors. Since she behaves well with them, her mother must have taught her to do this, and set a good example. Something else may be wrong with this child and it might be serious. I would stop practicing amateur psychologist at this stage and go to a doctor.

Also there is absolutely no reason to think that this person "will probably resort to doping the kid."