SSDI would take a while (6 months to a year for a determination), but she could at least apply just in case, with as much documentation and proof as she can offer them.

Apart from that, States typically have some sort of assistance for those who don't qualify for temporary disability (which includes some pay while disabled temporarily). These would include food stamps, Medicaid, and a small amount of money every week (but only if she doesn't qualify for temporary state disability). If she can apply for Temporary State Disability, that pays a little more and can be offered with food stamps.

The age does not matter regarding disability through SSDI, but it has to be a permanent disability, not a temporary one. It doesn't hurt to try. You can always appeal within the time frame, or update the information if an application is pending. If she is awarded SSDI while she is receiving State Disability, the State Disability will fall off and the SSDI (the highest amount out of the three) will be retained. Her retirement will then be based on SSDI when she transitions automatically from SSDI to SS Retirement.

I'm not familiar with FMLA, which sounds like Temporary State Disability.

Ask the doctor what her chances are of being permanently disabled, as seen through the eyes of SSDI, and see what the doc says. Additionally, ask the doc to fill out the form for temporary disability through the state. There's typically a long wait, but you can concurrently apply for Medicaid, food stamps, and other benefits for her in addition to temporary disability.