in the possible scenario, that the mother has autism or autistic traits, it would be plausible (extremely due her denying not having a child), that she could have went through major depressive episode or had full blown psychotic episode, which she would not returned back more normal state. This could naturally be scenario without even having autism.
She also could be using something ATM, but also could have decided to not take medication prescripted for her. This is all just speculative naturally.
Obviously she gave birth in hospital or similar, since the boy has been issued birth certificate. Also since he has been clearly been seen this year, it means she has had child under her roof.
I agree, that this case do not sound good in any means possible. And it definitely sounds like, that she is not capable of taking care of her son or even herself.
My questions for this case are....
1. Who and when was the child found autistic?
There is other devepoomental conditions, that might show up as autism to eye of an outsider.
If he was diagnosed, I would think he would had possibly get some financial aid.
2. Why didn't he get specific help for himself? (Therapies, special needs school etc.)
We definitely know, that he would had been recommended to get these things.
3. The mother, and her health status
Why did she deny having a child? Why didn't she pay her bills? Why did she keep her essentially hidden from outside world?
4. The height of the child
Why would people say, that the child didn't appear as tall as 11 y.o.?
Though some kids stay short and some just get growth spurts later.
5. Why was there no known pictures of the child
6. The possible motive
Was she embarrassed of her own child, since he wasn't your typical child? (so she decided to get rid of him?)
Was his condition too much for her? (Why didn't she get help?)
Lack of bonding with her child (This would explain lack of photos and denying that she has one. Not showing concern over her child, not getting him help. She could have viewed him as hindrance for doing what ever she wanted.)
Was she paranoid? Afraid of something? (She essentially was shielding him from the outside world. This could be seen as fear that something happens to him, if she won't do so. But it also means, she might have got rid of him, because of it.)
Financial issues (As bad it sounds, this would also back up of getting rid of him.)
Accident (These happen, but why didn't she call for 911?)
Less likely happening is that someone from outside did something for him or that the child was taken away by the child's father.
kinda OT, but have to be put out there: Autistic mothers are not necessarily bad moms - they can be extremely brilliant too and attentive. But they can be every aloof too and not bond with their child. Usually on these causes however, the mother would get help to overcome this.
Tho in this situation, it means her being aware of her own condition before hand.
I wouldn't discard it tho, but just saying!
But I do hope she is on psych. eval. and that the truth of this case comes out. Any child missing, taken, lost to natural and extremely to unnatural causes is one too many.