The person above me is spouting pure and utter nonsense towards you, she's never been put in a situation with anyone who actually took seroquel. She just "knows someone" and it works "well for them."
If Seroquel works on her, she'll be very tired often, and she'll easily sleep 24 hours plus and she'll easily gain weight from it. You could try to help her with the weight gain, if that's an concern(?), but she will seem out of it if it works on her. Seroquel is designed to sedate the person taking it. Its other uses are for a sleeping pill or someone with anxiety.
If your friend is or suffering from schizophrenia, they may start her at a high dose because it calms her down for the time being in the hospital. It may not, but you mentioned it does, and you've inclined it does calm her down. Out of the hospital is different.
In my opinion, and I'm no expert at all, I would ask about other meds and ask if they could start her on other ones before she is released. Abilify is the new one but it may cost you a lot. I would suggest looking up the second generation meds and bringing them in when meeting with the doctor and discussing each one out. Check to see which ones have a patent before as well.
Some Doctors will only suggest medicine that are patented because the get a kick back from it. Go with you think is right and right for your friend.
Good luck with your friend. I wish you the best.