Sometimes the parties can both act in good faith but they still can't agree. When that happens, and when no compromise can be reached, we have the courts to settle those types of disputes. I know the law, but your friend knows the facts about the day-to-day operations of her job and the resources of her employer--she would know better than me if her requests are reasonable.
You asked "can they force her to take the lower paying job or the one with no benefits." I may not have been clear. The employer is obligated to reasonably accommodate the employee--taking a lower paying job or demoting to a job with no benefits is not a reasonable accommodation.
You asked several other questions that I am happy to address to the extent possible:
1. "can she get ca stae disability if they let her go?"
A. Anyone who meets the state's criteria for SDI may collect. Generally, the function of SDI is to provide a partial income substitute for those who are unable to work due to their disability. If she can work in another capacity, she might instead collect unemployment, but SDI is a possibility as well.
2. can she file with the eeoc right now?
A. Yes. Whether she should is a question of tactics, but she can file with either the EEOC or the DFEH.