I agree, I can't see how this could be considered acceptable for your sister to live like this. I think they went into overkill with her meds, and she's over medicated. She will need to get help reducing it down gradually to an acceptable level. And she can get better, I'm sure of it... I know that feeling of being down though, and feeling hopeless because the whole world is so tiring. Reassure her that this isn't forever, and help her make an appointment and keep it. She'll need your support in this, as she won't be able to talk to a doctor by herself yet, she'll be too exhausted and confused. But you can get her there... and you will see her get better.

Give her a hug from me, and tell her I know it will get better.