[ToFundorNot]

I can't speak about California specifically, but in Canada, if it can be reasonably be proven that the illness was obtained at the workplace, the employer is required to pay for the sick leave by the local health benefits service (State/Provincial/Federal level), which in this case would be two weeks.

The employer can fight the filing, but in the situation of COVID-19, it's reasonably easy to prove it was a workplace based infection (multiple people will get sick).

Side note, when you get payments from the local health benefits service, there's a %90 chance it's being paid by the employer to the health benefits service, which then transfers it to the employee