About thirteen years ago, my mother became severely depressed. At first, she was just sleeping a lot. (She'd had a lot of stress during that period of her life: lost her only sister, a friend's son died, my own sister and brother were causing major headaches for the family, she was trying to run a failing business, etc.). I think our family doctor at the time had prescribed sleeping pills, and she became addicted. At the same time, my parents were trying to build a new house, and we had to move to an apartment while it was being built. This just made things worse.
For three years, my mom was in and out of hospitals for inpatient therapy. She was put on every drug known to man. Nothing worked. I was in college at the time, so I wasn't always home to experience this, except for the year after I graduated and moved back home. I remember watching her walk around the apartment holding our bill holder because she was so obsessed about not being able to pay bills. She was in sort of a zombie state. She'd go to bed for a while, get up and walk circles around the apartment, go back to bed, repeat. Once, when she went off her meds cold turkey, she became extremely violent and had to be removed from the house and taken back to the hospital.
When my dad realized nothing was working for her, the option for ECT (Electro-convulsive therapy) was brought up. I think it had been an option before, but my dad was afraid to do it. He realized at that point he had no other choice, except to put her in a permanent mental institution. I had already been married at this point and was living in another city, but I do remember the change it made. My mother still has short term memory loss from it, but she went from non-functioning (at one point, almost in a catatonic type of state) to being able to care for herself and, sometimes, my nephews.
That being said, my mother's quality of life will never be like that of a "normal" person. She has issues with her memory, and I've noticed lately that she seems to be sliding back into her depression. Of course, I'm not living with her, so I don't see how she functions on a daily basis. It's a day to day thing with her. I think maybe subsequent treatments might help, but maybe her therapists don't believe it's necessary right now.
Yes, shock therapy does sound scary, but medicine has advanced to the point that it is no longer the horror it used to be. It's administered in a safe environment by trained physicians. Basically, it triggers a seizure within the body and helps to reset the brain and release certain hormones. I've heard that more than one treatment helps. I can't remember how many treatments my mother had over ten years ago, and I don't know if she'd benefit from more. Good luck to your family member. I hope she finds the treatment that will best help her depression.