I give all of my parents the Ages and Stages Questionnaire at the specified ages. If there are delays noted in the checklist, then I discuss with parents, and recommend followup with doctors/community resources etc. When you say things like doesn't talk/roars only/not knowing how to play/doesn't play outside, these are big red flags to me. The ages and stages questionnaire can be done online, and you can submit answers electronically and get printed feedback from developmental experts. You can find it at www.fsca.ca and look up Ages and Stages Checkup. This child should be entering school soon, so if he needs support, it's better to get started now. I guess we all have different approaches as to whether to try and get the parents on board. I would, given the child's age, but to each their own...