You need to demonstrate that you and your wife are one unit. Do

the children, but show love and care between you. Make sure your wife is not subconsciously placing your son in between you and her.

Give your son the respect he deserves. Give him some responsibilities (such as taking care of his sister) that are withnin his ability. Praise him often. Pay attention to his effort. Ask him questions about his classmates, his observations about the happenings in school (such as who and who are friends), and delight in his answers (there are no wrong answers.)  Ask him to be respectful to anyone he meets, organize his thoughs in words (anger is the result of anxiety and fear, what is his fear?)

Ask him to pay attention to bigger things (what is reported in the evening news,e,g,).  Encourage school activities. Establish some routions (such as reading a page of a book before going to bed, children's Bible is a good start (stories, not religion)). Helping him understand the bigger world out there will ease anxiety.

Do not mention Asperger or autism in front of him.

 

Goof luck.