Friends' child stims and seeks out sensory play but his parents are oblivious... should I buy him something or would this be out of line?

Okay so I'm not going to try to diagnose someone else's child but we have a couple of friends who have a two year old who is almost the same age as our two year old. He is non-verbal and displays really obvious, classic stimming behavior. For instance, he will take a toy car and hold it right in front of his face and spin the wheels for ages. He likes to line up his toys. He walks on his tiptoes and flaps his hands and does that "looking out the side of your eyes" thing, not sure what it's called, but I have HFA/Asperger's and all of these behaviors are super familiar to me. I was an early talker but I engaged in a lot of stimming type stuff growing up. I don't want to tell the parents it really seems like their kid has some kind of spectrum disorder; I've already hinted around and they're patently oblivious like it might be intentional. (I.e., When they expressed concerns that he wasn't talking, I asked them if they'd brought it up with the pediatrician and they said, "Yeah but they want him to go to some early intervention crap. He doesn't need that!") And they buy him regular toddler toys (talking Cookie Monster, action figures) and then complain about how he's totally disinterested.I remember really liking certain things growing up, like kaleidoscopes, those 'liquid motion' toys where the little beads of colored water drip through oil, a wand filled with some kind of thick clear stuff where sparkles and beads would slowly fall from one end to the other, etc. I feel like if I could convince them to get him something like this, he would actually play with it. But if I point it out in a store, they act like it's not a typical boy toy and they don't want him to have it or they think it's random, etc. What if I just ordered some of this stuff and had it sent to their house anonymously?? Would that be totally weird and creepy? (ETA: Okay so a no on sending it anonymously... what if I send it with my spouse and my name on it? Better?? Still random though; unless I act like it's a late Christmas gift maybe...) I just feel bad for their kid. They absolutely do NOT 'get' him and don't try. It's like they prepared to have a certain child and even though he's not what they envisioned, they're proceeding as if he is. I want to help him somehow because if my parents had been like that, my childhood would have sucked. via /r/Parenting http://bit.ly/2QQzlZY