My close friend's DS is 2.5, and each time I see them (every month or so) I notice small behaviours that could be signs of being on the spectrum. I have no experience of autism but having read a few guides about the symptoms, I am increasingly certain friend's DS is matching many of the signs.
I haven't mentioned any of this to my friend, I have no idea if she has the same thoughts/concerns. My friend has been struggling a bit with controlling her DS's behaviour and gets increasingly frustrated and cross with some things he does. My only reason for suggesting she investigate this is so she finds new, positive ways of dealing with her DS. She has told me more or less that she often feels like she's failing in her parenting 
Would you bring it up in conversation, or butt out?