Google isn’t the only company that does this. It’s very common shitty thing that happens across the US. There needs to be some sort of law that protects parent’s jobs when they come back from leave.
Employers are required to pay out a certain level of comp when someone is on leave, but they could also just pay you a lump sum and cut ties. Then you’re fucked after leave ends.
There also needs to be good enforcement. We made a law protecting the jobs of National Guard Soldiers called up for Iraq and Afghanistan and employers just didn't care. Enforcement was extremely lax, basically having to personally pay a lawyer and employers had a million excuses the courts accepted.
Or you do what we do with the ADA - create new rules and let people sue when they’re violated.
If you make the cases easy to win with clear evidence, then lawyers will throw up billboards asking for business and they won’t charge unless they win.