LinkedIn doesn't allow one to differentiate between being enrolled in a PhD program, or having completed a PhD program
The common practice when enrolled in a PhD program is to list using a future completion date, making clear that you have not yet completed the program.
Google knew he was enrolled in this program when they hired him.
It's just as likely he was fired for lying about having a PhD from Harvard.
Edit: I stand corrected, he was just enrolled in a PhD program.