A lot of places claim they want to hire extremely smart autists, and some do. But these types of employees are incredibly hard to manage. Imagine herding cats. So if you don't invest a lot of effort in building an environment to let this person cook, go down the right rabbit holes and not rub others the wrong way, a person like this is a huge liability to the org.
Please, explain how you determined this person was an "extremely smart autist".
A lot of companies who claim to want highly intelligent and autonomous engineers by revealed preference actually want glorified slightly above average ticket pushers.
At least by the looks of it, Jane Street appears to be an odd one to genuinely value competence.