I am a mother to an autistic boy, he is 4 years old. Each child on the spectrum is different, each like their own things, have things they dislike and yes have their own problems.
His young age is actually good for your family and the adjustment. It will probably not be easy nor would it be easy if he was a 'normal' kid. All things like this take time and adjusting.
my suggestions are the following..
Talk to his mother, find out what she provides for the child when he is having a hard time with something, something that soothes him, comforts him or can distract him from the unnerving matters he is dealing with.
Find out what he will eat and wont eat, a lot of children dealing with autism have very uncontrollable food habits, this is NOT due to behavior. this is due to over acting simulations with the textures of the food. For example my son can not eat anything like apple sauce, pudding, whipped cream. The texture is the problem.. If I tap just a teeny tiny amount on his lip he will lick it away but does have a emotionally hard time with the fact that it was placed on his lip.
Find out what he is currently taken with, for example my son and his letters or numbers or anything electronic in combination! This solves problems with his melt downs in public places.. Its something he can focus his energy and attention on that doesn't overwhelm him. Pretty crucial in my diaper bag.. diapers.. check.. wipes... check.. his ABC Vtech toys check.
Do not try to force any physical action on him. Some children have a horrible time even LOOKING at you, some do not speak at all some can not tolerate touching of any sort, hugs, kisses, rub on the back.. ect. Do all you can to understand this child.
And please remember, somethings he can not control. Patience and understanding is key here. And good luck on your new angel in the family. He will bring so much to your life you never knew you were missing. Each child with autism is fascinating and you're lucky to know him, protect him. Stand by him, and mostly importantly never give up on him.
I am Special Education teacher and work with students with autism. My tip is to keep a routine. Children with autism don't like changes. Try to keep a consistent schedule and avoid moving around as much as possible. Let them know in advance if there is a change in his daily routine. That last thing you need is a meltdown! Best wishes!
There are some good books out there. Just avoid anything written before say, 1970. Anyrthing by Temple Grandin (she is an expert, since she has autism). Tony Attwood has something out there (he has AS).
Get in touch with your local chapter of the Autism Society. If no local chapters, you can find the autism society of america at 1-800-3-autism or w (cubed) dot autism - (hyphen)society period org . autism national committee is good, too. w (cubed) autcom dot org.
From what you read, you may or may not observe all of what is mentioned. So, you can pick and choose what you read.
To make him comfortable: Nothing flashy, just keep a plain house. Keep a routine that is very predictable. No changes in routine (think army).
I had a post recently about movies featuring characters with autism, but I can't think of any with anyone under 3 years old. Boston Legal has a character who has AS but please DON'T TAKE THIS PORTRAYAL SERIOUSLY. Christian Clemson plays a lawyer, Jerry "hands" I don't take ANYTHING on that show SERIOUSLY!!
You can try reading some of my journals to give you an idea what it is like from an autistic's perspective. My dad should also be on here soon. He's got some helpful journals on his profile.