Every child with Autism is different. There, I said it. Just like every 2-year old has their own personalities, every child on the Spectrum behaves in a different way to the same stimuli. In fact, whenever you have a disorder of the mind, even though some behaviors are the same, what sets those behaviors off can be very different. This is a very important fact to know when you notice someone with a child with Autism.
For instance: Autism runs in my family (and my wife's interestingly enough). Some in the family are runners, and will do anything to just get out and run. Others, like my son, is a problem-solver, and looks for ways to get around any barrier he finds (even if it is for his own good). Some only have a couple of behaviors, appearing a little slow in their social interaction but still being very focused and knowledgeable in their tasks. Yet relatives still say, "Well, your son doesn't do X, or he does Y which will lead to Z", as though they know the roadmap for my son better than I do.
Let me first say with all love that relatives mean well. They are concerned for me and my family, and they want to help. But what they don't realize is every attempt to break that delicate balance of sanity between work, working with my sons, keeping up on schooling requirements and techniques to augment at home, and contribute with the house work just creates more stress. And while they are trying to help me focus on caring for my child, they don't seem to see that I'm already doing the job by doing everything right as recommended by his teachers and school psychologists. Instead they see the broad difference between my child's development and those of his neurotypical cousins, and want to push me to push him even more.
You see, a parent of a child with Autism has to be a Super Parent to begin with, just to manage their son's or daughter's condition. We are constantly aware of the environment, trying to make sure that it will not be too stressful through sensory overload. We look for key signs in our child as a method of communication, making us hyper-aware of our children. On top of this we are constantly looking for ways to help our children develop normally and become self-sustaining, contributing members of society. Most parents try to do this anyway, but if they have a child with Autism, they are constantly on their A-game, and it will wear parents out.
So what do you do? As a parent, you need to find some down time. You need to find some time, even if it's in the middle of the night, when you have a chance to relax the brain. Some communities have respite services that allow for a couple of hours a day of free time while their child is being watched by a professional care-giver. This is a great idea, and something every parent should take advantage of when available. For those who do not have this service, they need to find a trusted care-giver that is willing to take the children for short stints when necessary. Generally it would be family members, but it could also be good friends.
If you are a family member that is looking to help, stop trying to look at the child with Autism as an Autistic child. The child, the little boy or girl, is a child first. They have needs like a child, have a personality, and just wants to learn and grow like other children. Instead of trying to stress out the parents by telling them what to do, try engaging with the children. You will get a better feel for the child's abilities through these little stints than otherwise, and can perhaps help the child make intelligent connections between behaviors (i.e., relating sign-language with speech). This doesn't mean that is the ONLY way the child will learn, but it's the way the child will learn with you. Go with it, and enjoy the time. Let the parents worry about their children. There are exceptions to this, but for most parents of a child on the Spectrum, it's pretty common for this method to work.