Having been out of work for an injury in the past for a long time (4 months), HR laws are a mess in CA. The employee has hoops to jump through if they want to keep their job (FMLA paperwork, workmans' comp, etc.) and the employer has hoops to jump through to keep the employee since CA is a right-to-work state and can be terminated by either party at any time.
Your wife should
call the CA Labor Board - they can answer these questions and do so for free (okay, time costs). They can explain the requirements for compliance with the law, what your employer is legally required to do and what the employee is legally required to do.
I can only speak from my past experience, but I filed the required FMLA paperwork and was able to get my exact position back - even though they hired a temp to fill my spot while I was out. Had I not filed the FMLA paperwork they could have laid me off once I hit the 30-day mark and paid me all past-due wages/PTO/Vacation, etc. and hire a full replacement.