There are many developmental red flags here, especially when he's almost 4 years old. If you google the Ages and Stages Questionnaire, this will give you a detailed screening of the major developmental areas. Don't use the "ASD" label, but alerting the parents to his skills/goal areas is something I do for all clients, even if everything is going great. I guess it's up to you,and how much you can handle. I personally always try to get parents connected with community resources before they hit kindergarten if there is a need. If you can't last that long,then interview,and terminate the family.