Good advice that is applicable towards doomsday cults as well.

Is there any evidence to suggest that a "brain chip" will ever "cure" autism?

What would limit a brain chip from accomplishing that goal?

Current understanding of autism is that it is a developmental disorder, and not something characterized by excess/insufficient hormones. It is hard to imagine how a disorder that challenges information processing in the brain could, with our very limited understanding of how such things actually work, be handled by a chip saying "You should respond to such stimuli in X manner, not Y manner". It's not a case of "X is handled incorrectly, tell the brain to do Y instead".

I could potentially see such a thing working for, say, epilepsy, where we might be able to "mute" or counter a stimuli that causes seizure, but, at least for the forseeable future, I don't see "brain chips" working in contexts other than concrete causal links, stimuli, reaction/response mechanisms - I think one hint is that there's nothing we can do to "medicate" autism. Medications currently used are for "byproducts" of ASD, such as ADHD, anxiety, not the disorder itself. Indeed, the closest (and we're not particularly close) we have come to thinking of how to manage ASD is gene therapy, which wouldn't be manageable by a "brain chip".

Autism is a broad spectrum of behaviors, but one consistent symptom is not being able to “quiet” excess stimuli (as I write this my daughter exhibits her self stimulation behavior by running back and forth across our family room).