He had 0 to do with the TPU.

I was hired around Google around the same time, but not nearly as famous :)

AFAICouldT it was a "hire first, figure out what to do later", and it ended up being Swift for TensorFlow. That went ~nowhere, and he left within 2 years.

That's fine and doesn't reflect on him, in general, that's Google for ya. At least that era of Google.