Hi Ludi- Sorry I didn't post already.
I'm very mentally ill & work full-time, but it's been a real struggle.
To begin with, employers won't generally hire mentally ill (m.i.) people while they are showing symptoms. THey will fire you if you have already been hired because traits like apathy, withdrawal, anger, depression, etc. do not fit in well in the workplace & appear "deliberate" as compared to , say, a broken arm or heart attack.
There are programs that allow many m./i. people to do at least a little work to feel better & get some experience. I worked at a pet supply co-op when my illness was very bad. I recall going from the inpatient ward to my job, which was on the grounds on the mental hospital, & then back to the ward, when I was at my worst. I don't know if these programs exist in the US but there are a few around here.
Canada Pension is very good about helping you get back to work, but I don't think there's an American equivalent. They don't cut you off until they are sure you can support yourself without them.
I would say important factors in working while m.i. include: finding a job that doesn't make stress worse; making sure you can do the job with your illness;
making sure you can afford your meds & taking them (a benefit package helps); making sure you are able to take time off for hospitalizations & regular appointments; having supportive friends/family/co-workers.
I also suggest keeping the m.i. under wraps as much as possible in the workplace, because there is tons of prejudice against m.i. people.
Most of all, don't listen to people like Tame & certain others who seem to believe that m.i. people should be doing the crappiest jobs available no matter how m.i. they are. I have no doubt that 10 years of scrubbing floors/toilets, serving coffee all night to drunks at a donut store, exotic dancing, commssion-based retail sales & the like made me more paranoid, aggressive & depressed than I was before I workled those jobs. FIND SOMETHING THAT WON'T AGGRAVATE YOUR SYMPTOMS.
Ludi, I hope your sister finds the help she needs, & I think a transitional supported workplace may be the place for her while she's still symptomatic. However she NEEDS a better doctor if she expects a better recovery.