Possibly stupid question but how do they test him for autism without his malingering interfering? Is there a physical component that's testable? If it's some sort of standardized test he's going to give the most autistic sounding answer every time. Most people being tested most likely do *not* want to have autism so answer truthfully.
Andy's biggest issue is that he overplays his hand.
To the unfamiliar his little act is quite convincing, the speech patterns, the baby talk, the look (he puts his shirts on inside out and backwards and lately he always has his big ass ear-pro on) so I'm not surprised that he fools most lay people.
But to the educated and familiar Andy is definitely off. He has all the signs of autism. And I mean every last one. He checks every single box on the list (hell he checks some of them twice he so autistic) which is a immediate red flag. Only the most crippled autistic would have every single aspect of autism. If Andrew really had all these symptoms he'd be a useless shell of a person who would have spent their entire lives in a hospice at the least.
But we know Andy's symptoms showed up around 28'ish which is just not something autism does. So that a another big red flag
Then you have his tells, which he has problems keeping consistent, especially when he's upset or angry, they come and go randomly and are very obviously displayed for effect. He always punches them in between his word to make sure people understand him which is not something a true tic does. Another red flag
Then of course you have his perfect recall and use of the statues of both civic law and the ADA. No autistic person at Andy's faked level would be both able to recall them and more importantly use them so effectively when he needs them. Andy's getting in over his head, whelp bring out the civic law statutes and run away. Not doing what he wants, quote the ADA at them and threaten them with a lawsuit.
Again...way overplaying his hand.
So in short Andy's just good enough at playing pretend to fool the average person. Those familiar with actual autism can spot him a mile away and mostly do so. The doctors, the nurses, the hospice care staff they all peg Andy as a faker within a few hours tops.