Thank you for your reply. I think I will do a checklist and recommend they see their doctor.
I've done a few for the child and they are fairly consistent, the child may need early intervention. The doctor wouldn't pick up on these issues because both parents are in huge denial and refuse to tell the doctor anything except that their child has no concerns. I have three children of my own and strangers often comment on this child and it is breaking my heart stressing about this child because the parents do not seem concerned. I will bring up the milestones eventually and ask them to get the child assessed. Thank you.