How is she going to have another woman's child evaluated?
@ Jewelbox - if you suspect something is amiss you should contact the authorities. The child is more important than your friendship but be prepared to be (hopefully) wrong.
+1, yes just make sure that you can accept when you are wrong aswell. But it is 100% correct of you to have worries if the child is acting strange.
I do not know where the child's father is; he pays no child support is all I know.
The child goes to a daycare; not sure where, but will find out. Will then have a talk to the person who takes care of her and maybe get her to also talk to my friend about the child's strange behaviour. What do you think about this idea?
Maybe alert child servises that they could send a psycologist to evaluate all the kids at the daycare to make it less of a "direct" search for answers.