Ethics on telling a parent you are concerned for their child developmentally?

I read a huge thread a few weeks ago filled with comments going off on the audacity and rudeness of people who suggest they put a cap on their baby in the winter, so it made me hesitant when I met my new friend and her 2 year old son.I work with autistic kids. My husband is a special ed teacher, most of our friends are in the SPED world, and in fact I met my new friend specifically because she AND her husband are special ed teachers as well.So I'd seen her son at busy gatherings and never noticed anything unusual, but that was because I was either in conversations, drinking beer, or minding after my own kids.Then the other day, I noticed something. Her boy was spinning and doing the side-eye in the middle of a gathering, and it struck me as very...distinctive. Other adults were there laughing at his behavior, joking as if it were normal 2-year-old stuff (not in a cruel way, but the way people laugh in a "that's so cute" way). I felt uncomfortable laughing along, and paid more attention to him throughout the day/evening.He doesn't talk. I was talking to his mom in a 'get-to-know-ya' kind of way and she made a comment about how he isn't talking very much. I played it off and did not comment further. He also doesn't respond to his name. Like, ever. It's been 3 gatherings now where I've been watching and I've noticed he is completely disconnected from everyone. He does not initiate social interaction. He does not easily respond to his name. I watch his parents get like right up in his face to be like, "HEY KIDSNAME" before he seems to acknowledge them.Finally, at Thanksgiving we were at a friend's house and they had some speakers in the backyard with like....a digital LED graphic on them. This kid comes over like a moth to a flame. He stands at a distance for a while, transfixed on this thing. Then he eventually gets like RIGHT UP to it, and is STARING for seriously like a solid unbroken 10 minutes. STARING. Not pointing to it, not gesturing, not vocalizing, not responding to his name. Absolutely zoned in and transfixed. I heard his parents from a distance, and one of them seemed to be gesturing towards them and she said, "Oh, it's green. You know how he is." I happened to walk up at that moment and I was like, "Oh haha does he really like the color green?" I dunno, I didn't even think about it, I was just making conversation as my daughter was tootling around in the same area. My friend looked at me and was like, "What? Uh no,"It was really weird, but I changed the subject and moved on.I think her kid is displaying some pretty concerning traits of autism. I kind of want to tell her. Having worked with autistic kids myself, some of his behaviors are really indicative of something going on. The spinning and side eye thing is a pretty common stimming behavior. Lots of toddlers can get zoned in, don't cooperatively play, etc...but this kid was on another planet. He was NOT displaying any type of communicative behavior. Once you start paying attention to it, it becomes really obvious.Even my friends' speech-delayed 2 year old was showing active signs of communication: noises, gestures, eye contact, smiling, interest in others, etc. This kid wandered around and stared right through everyone.Anyways, I am assuming I just need to mind my own business and let these people sort it out on their own, right? via /r/Parenting http://ift.tt/2ABR9im