I really wish I could offer advice, but I have yet to find the answers to this question myself. I don't think there is much she can do when it comes to the shortness of breath as her growing uterus is pushing against her lungs.
As for the difficulty sleeping, I have found that firm surfaces help me sleep rather comfortably. My bed is very soft and I find it only makes my hips and back ache when I wake up, so I decided to give the sofa a try and I wake up refreshed and pain-free. She can also try propping herself up with pillows and sleeping with a pillow between her legs.
And for the aching back, I recommend back rubs! My husband gives me back rubs with lots of pressure to help relieve my pain and if that doesn't work, then generally a nice warm bath does.
Good luck with the rest of your journey, guys! I hope she can get as comfortable as possible!
