I've been told that DS needs an organic diet entirely free from sugar, additives, and anything processed. Also no screens. This will cure him. I'm going to sell this secret to medical science and make a fortune.
I used to heard the good hiding/good hard slap one from the in-laws, they used to say that if I should smack him so hard he'd not be able to sit down and that would sort him out. Solved it by cutting contact with them (not just because of that, there were other reasons).
Been told it's lack of discipline.
DS had a meltdown at the leisure centre one time, he didn't want to go home. I ended up having to carry him out, leaving DH with the other kids, to find a quiet corner where he could finish his meltdown and then get over himself. As I walked out, a woman was staring and tutting and made a remark to the man with her about DS needing a thick ear. I lost my rag and snapped "had a good fucking look, have you!? I should give you a fucking thick ear you ignorant cow!" Not my proudest moment but it had been a long day and this was in the early stages of 'we know something isn't right with him but we're not quite sure what it is' so very stressful for us all. Anyway, DH said afterwards that as soon as I was out of the door the muttered conversations changed from "that child needs a smack" to "poor thing must get it from his mother" :o
I'm going to be sitting pretty come retirement as DS will be a computer genius and/or the next Stephen Hawking/Einstein. All ASD people are freakishly good at maths, science, and computers so he will get an excellent job, probably as an inventor or as a mega super genius in charge of cleverness, and will be able to support me in my old age. I've picked out my mansion already.
Then there is the opposite direction, often from well meaning friends and my parents, who will give in to his every whim "because he doesn't understand no".