ESA Meltdown

I have a 24 year old son who has Fibromyalgia, Asperger's, Learning Difficulty, Memory Impairment, and Cognitive Impairment. Had ESA Support group awarded after face to face 2 years ago. Filled forms in again back in Feb and requested to go to a Face to Face yesterday. Arrived to be told no recording facilities as we had requested in writing, downloaded from members guides on here. After waiting 1 hour 15 minutes we were informed my son could not be seen and his appointment cancelled. We will send a new one out in the post. His condition has not changed, same and more supporting evidence was sent in and his care needs have not changed. So in front of everyone he had a meltdown because he wanted to be seen as his appointment was that day. He wasn't budging and unfortunately became really verbal and abusive towards me, something I am used to because of his condition. Fast forward to home, medication and knives removed due to threats to self harm and nearly had to call crisis team. I have contacted ESA today and explained what has happened. The guy said he would make notes and ask if they could do a paper based assessment, however I am afraid that this would not go well in his favour and he really needs to be in the support group. Or they may call him back for Face to Face again. I am dreading either as his behaviour is so unpredictable and if they do the same again I am afraid of how he will react. Any advice on how to go forward as I am on the verge of contacting my MP for what use it will do.

Thanks Gordon, our GP practice are not so good and I have followed all the guidelines on here along with a massive amount of evidence. He has an ongoing award for PIP and gets higher rate for both care and mobility. Our daughter is also Autistic and she was awarded ESA support group no F2F for 3 years. Can't fathom it but will just have to cross each bridge as it comes. Thanks again.