Also he has a background in bio, and managed to land a full stack and ML engineer positions, implying he is self taught, and therefore should be already fairly intelligent...but he decided to go get his MS in CS, without even doing any research project and just opting for the GTA instead of GRA route.
None of us can really know for sure, Im just saying it smells a little fishy. If his resume came across my desk, Id have some specific questions about his experience. If you are that smart to have a background in bio, and land the jobs that he did, your career would look very different.