Native French speaker here - “C’est la vie autiste” would work better I think.

“C’est la vie de l’autiste” would mean “This is life for the autists” - which, to me, has a slurry connotation.

“C’est la vie autiste” would mean “This is autistic life”

To me it depends on the context. In a new job, I take a humble stance and repeat to myself:

• I don’t know the full context
• I don’t know who is smart and and who isn’t
• I have my own biases

And I just work according to instructions assuming the higher up’s have a roughly good idea what they are doing.

After a few months, you can start understanding the broader context and spot some mistakes. Then you can start making suggestions.

It’s not a bullshit rationalization, she’s absolutely right. And given her level of analysis, if her parents have a legit reason to ask her to fix her behavior they just have to say the actual thing instead of relying on trite bullshit.