IIRC he works (worked) for Verily, and previously was at Valve working on their VR hardware. He's also mentioned having a business pre-Valve that made MRI safe controllers for users to interact with computers while inside an MRI machine.
Also, really the holy grail of YouTubers — he’s not concerned with clicks or retention. He has a day job, he’s not trying to do this full time or make a career out of it. I’ve been following him for years. Legitimately just an insanely smart person doing projects on his own time he thinks are interesting and that he thinks other people might be interested in too. It’s kinda crazy when it’s as simple as that with no ulterior motives or incentives.
I believe he works at Alphabet (tangent?)—somewhere in the Bay Area.