15 year old DD being mean to 13 year old step sister. Constant nasty digs at her, but claiming it's all jokes and banter
In the last two weeks she has called 13 year old fat, incompetent, and useless. Has also made nasty comments about 13 year old's disabilities, pointing out lots of things she can do that 13 year old can't manage, eg running, balancing, lifting heavy things, and stuff which involves coordination. Saying in front of 13 year old that she is prettier, slimmer, taller, healthier, and has nicer hair. 13 year old has ASD, ADHD, and dyspraxia. Girls were previously close and haven't argued, and 13 year old is sad and bewildered. Currently making sure they're not in the same house at the same time. Attempts to discuss with 15 year old have been fruitless - disingenuous claims of banter. WWYD?