I am under the impression that the cash benefits are only available in the more extreme cases. I've honestly never looked into it for our family, no one has ever suggested it as being even remotely possibly available. We HAVE looked for free or reduced cost services to tap into, and even that can get complicated (my son receives counseling through a community clinic, and we thought that by being accepted they were saying he qualified but, no, now they are asking for insurance and income information from us, telling us that we are too "wealthy" to get this for free - um, shouldn't they have asked THAT before enrolling him and providing this service for a month?).
If you are having to make major life changes to accommodate your child's needs, or must access costly private services because you cannot get what is needed through the school district and other public agencies, then definitely look into it. But I think most of us count ourselves lucky to get services through public agencies, and leave it at that.
Once he is an adult, if he has not been able to achieve independence, THEN I know disability or SSI can be applied for (I think it's still tricky, however).
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Mom to an amazing young adult AS son, plus an also amazing non-AS daughter. Most likely part of the "Broader Autism Phenotype" (some traits).