OMG. What an awful ordeal that must have been.
It is entirely possible this child has some sort of disability (as alluded to). I had the honour of co-parenting a severely autistic boy for 9 years. His meltdowns and tantrums were something to behold. HOWEVER, the fact that his mother does absolutely nothing other than offer mere platitudes is the most shocking thing. I certainly couldnt have stood that and I would most certainly have used any amount of bribery, cajoling, remonstration, or my quite well known "evil stare with the pointy finger" to make the little *** sit down and shut up.