Moms with autistic children

Moms with autistic children (or people who work with people with special needs), I have a situation I need help with. I recently started working with a child who has autism. Unfortunately, I have not had the opportunity to work with many autistic children, so I need some pointers on what to do and what not to do while interacting with him.
Some background information: he is a very sweet boy who is five years old. He is very intelligent, but has difficulty with speech and communication (like most with autism). He gets very overwhelmed by sound and the other children. He gets very upset when asked to take care of personal hygiene (washing hands, etc). He enjoys being near adults at all times, and has no interest interacting with peers. He would probably love to be outside alone with an adult, but unfortunately that is not possible. Also, he will hardly eat.
I am planning on having a meeting with the parents.
What pointers do you have for me?
How can I make him feel less anxious and overwhelmed? Should I ask for eye contact, or is that too much? How can I best communicate with him?