I would think inappropriate language by E would be disciplined, especially if it is hurtful to your other child. The sibling has to be protected. Just because someone has autism does not give them permission to use hurtful language to anyone (does he say mean things to you?). I understand he may be "brutally honest" but mean words have to be stopped and changed.

Sounds like he needs applied behavioral analysis -ABA-to correct his behaviors and speech to teach appropriate language (family can help with language by giving him correct way and words to use).

I don't know-it sounds like he could be dangerous. You should NOT leave him alone with M and you need to get him help.

The siblings (without autism) often need counseling to understand why their sibling with autism does what they do. Once they understand that the child with autism has a disability and a problem they were born with and need help with, they understand a little more. Obviously they have to be old enough to understand it all.

My youngest and only NT has only known autism since he was born since he has 2 older brothers on the spectrum. He too has picked up some very bad habits along the way. Some things that helped us was to have scheduled play time together. Find something that E and M are both interested in and have playtime together. With us it started with simple things like playdough but with E being older he might not get into that. We also frequently did fuse beads. I usually picked something that was crafty, designated a set time, and once that time was up all 3 boys were encouraged to go their separate ways. Make sure to pick something that is more geared to parallel play at first. I always let my oldest know that he would earn extra time with a desired alone activity for successfully playing with his brother. I started this time really short and gradually increased it. Once the time was up I kept my youngest busy doing other things away from the oldest. When my youngest started preschool we did not have any problems with behaviors, he quickly fell into routine with the rest of his peers. One great benefit that we have noticed is that other students behaviors don't seem to faze my youngest. In Kindergarten this year his teacher quickly realized that my son didn't react to a little girl with autism like the others did. He never removed himself from her and when she had outbursted he kept working.