Here's a couple of things for YOU to read and and compare against the DCB. Print them out according to the child's age and go down the list marking it with yeses or nos. Make notes in the margins of things that you have seen that jump out at you etc. Then take a look at your notes.
Does your DCK not do a lot of what's on the developmental milestones? Not all kids develop at the same pace and might fall behind in some areas but that doesn't mean that there's a delay, if however you notice that the child doesn't do a lot of what's on the list then I'd show any articles of what you have already found and give DCM these and copies of the assessment that you did which includes your own notes.
Remember though, all you can do is recommend that she take him to the Dr but she might not and that's her decision and you'll have to resect that.
I'm not sure how old your DCK is....
Developmental Milestones-University of Michigan
Call your pediatrician if your child: 0-36 months