I'm only 18 yrs old and was diagnosed with ortostatic hypotension. Low blood pressure is subjective (so I've seen). For me, 104/54, would be a little lower than what I'd want. I have a tendency to get really light headed and temporarily lose my vision, and I have also been known to completely pass out at times. Once I even hit my head on my wooden desk in my room, giving me a mild concussion. Anyway, I've had much lower. Unfortunately, when I'm end the doctor's office it of course raises a bit and kinda throws off the blood pressure reading. But I've also had like 90/60.
I also take florinef acetate to raise my blood pressure and it works great once I figured out the right dosage. I have to take two .1mg in the morning and two more in the evening.
As for the other medical conditions she has, I completely understand. I too have my own to deal with, and that in itself, is depressing. If she's not sleeping very well, have her take some over-the-counter sleeping pills. I know that with sleeping pills you can still feel tired in the mornings, but if it helps her get some rest and doesn't disrupt her dialy routine too much, then I think she could try that.
I wish you and your daughter the best of luck.