Damn, I just typed a long post about coping with other mums and it got lost.
basically, in public, I allowed, even encouraged, all the remarks about being "clever" and a "future engineer" and even "your kids are too clever to talk". I was always super-positive about DS2, talking about how fun-loving and affectionate he was. I made it clear that I didn't envy their kids and though he was the best boy in the world. I used the term "language delay" freely (eg to explain why he didn't answer a question) "oh, he's got language delay, it runs in my family.". So basically I talked openly and comfortably about his communication problems using the term "language delay" but never complained about him, always made it clear that I was fundamentally optimistic about him (and rather enjoyed seeing them worried that he might end up being a dark horse and outshining their kids!). I had my armour on. No one ever raised the term "ASD" with me.
But then back home I got down to work, serious long hard work.
I commend "It Takes Two" to you (it was the best £65 I ever ever spent in my whole life and if I ever do any fundraising it will be for the charity that publishes this book) because it is optimistic, clear, has no stupid milestone charts, no talk of syndromes, disorders or pessimistic terrifying throwaway anecdotes. You can leave it lying around on a coffee table/show it to your mother in law and it won't start an awkward conversation - in fact you should show it to everyone on her "team".
Anyway, as I learnt to accept the extent and nature of DS2's problems (and thinking about ASD was an irrelevance to that by the way - a distraction from it), the way I played with him got more tailored, more expert. He started to progress fast. And that was so exciting that I no longer cared what other ignorant mothers with their dull neurotypical kids thought.
happy to talk any time. It's all about finding your individual way of coping. like you know how some people, when they are ill, need to be "in charge" and know everything about the illness, but others need to feel they can just lean on their doctor ?- and both those approaches are fine - we're all different.