You set the example. You, a spouse, and other family members are the foremost role models for your autistic child. This is a HUGE responsibility but also a tremendous opportunity.
No parent or family is perfect, but having a special-needs child in the home can help you to do better, to become a better person. If you practice showing love, your child is much more likely to reflect your example. If you scream and shout, so will they.
Some autistic children are going to struggle in any family situation, but you and your family can unite to provide the best home environment possible. Any struggles with Autism will be much easier to tackle if there's love (and plenty of humor) in the home. Again, your home life doesn't have to be perfect. I can't stress that enough. But there are things that each of us can do to improve ourselves and how we react in any frustrating situation. A supportive family unit is key to you and your child's success. If you don't have that, you can create it, no matter how large or small your family is.