(disclaimer: I am going to generalize for simplicity sake. Autism affects every person different. They have their own set of skills and deficits, like everyone).
One of the significant problems of autism is the sensory. They do not filter out input the way a typical person does.That is why you will see a person with autism wearing headphones. They are extra sensitive to sounds.
They are extra sensitive to all sensory input.
That is why it is important to be calm when dealing with children with autism. Sometimes this can be impossible, but they do respond to calmness. If you can maintain a low heartbeat, slow breathing and a calm expression, their body will try to match it.
So if you can, sit close to them and remain calm and remain safe, then they will respond. However, you have to use caution. This leaves you open for a hit or bite.
Choose safety first.
After All, we have all been so angry we have wanted to hit someone or something. The thing that stops us is we identify others feelings and we know the social norms.
These are two things children with autism have difficulty with.
If you are upset, you will give off cues. Those cues come at a child with no filter strongly and there body gets even more overloaded.
This is why (and it is hard), as a aprent you should look into respite time. Autism is hard on you health and your marriage. Take help so that you can be at your best.