It is a spectrum disorder. It could be that the child you think is fine, isn’t. I don’t know, but in cases where the child is highly functioning at some things, he may be clueless in others. There are kids with autism who can do all their homework in an hour, but can’t tie their shoes even after 10 hours of occupational therapy.
It is very cruel to belittle your neighbors and friends who have a kid with autism by not believing them. Of course dx can be wrong, but give these parents the benefit of doubt.
They don’t say their child has autism (because nobody would believe them); they use the catch-all “autism spectrum” because it is so vague. NOBODY (including their closest friends) believes them.