Hi My Son Is 20 Years Old And We Have

Hi my son is 20 years old and we have been a bit concerned about the troubles that he has socially. He is very intelligent and has been studying engineering but has returned home to live with us because he has struggled emotionally and financially on his own. I asked him to take the test for high functioning autism and he had a result of 36. He is not phased by the result in fact it doesn't seem to have surprised him. What should I do to see about a diagnosis and is it going to help him if he is diagnosed.?