I have a four year old son who is diagnosed with autism spectrum. As a father I would like to know from adults with autistic tendencies what I should do to make

I have a four year old son who is diagnosed with autism spectrum. As a father I would like to know from adults with autistic tendencies what I should do to make him happy and to help him grow up to become independent and self-reliant and what I should avoid. Autism spectrum is a very wide field, I realize, so I tell you that my son probably has neither Asperger nor AD[H]D, but perhaps early infant autism and as it seems not in a very severe manifestation but distinct enough that I sometimes have to explain it to other parents at the playground, for example. August he will start kindergarten in a private school with Montessori pedagogy, in fact, he already attends a playgroup there two times a week and one afternoon outside in the woods and he always returns happy from there.