You were exactly right that children mirror adults' behaviors. Thus, if your girl's primary care provider during the day happens to be your mother-in-law, you and your husband need to sit down with her for a constructive discussion. If the discussion does not work, I suggest you bring in experts to help with the situation. You can contact your girl's pediatrician for help. Pediatricians can identify and address developmental and behavioral problems that result from exposure to psychosocial stressors. Make an appointment with the pediatrician right away and take your mother-in-law to the appointment. You should not wait any longer for the situation to turn around because young children need a positive nurturing environment to build self-esteem, and sense of security as well as confidence. If all attempts fail, your little girl should be removed from her grandmother's care immediately.

My boy was not potty trained successfully until he turned three years old. Each toddler should meet this challenge in their own way and at their own time. Forcing them to do so when they are not ready can only cause backfire. Your little girl seems to be traumatized by the experience. Your mother-in-law's behavior is harmful and should be stopped immediately.