Hi NeverEnder--I hope you're taking care of yourself and your own sleep cycle...I know when mine gets thrown off, I'm in danger of an episode. Please take care.
So, about spending time with your friend: what about spending time beside her while she's sleeping--either reading in bed, or something of that sort? Is that even a helpful option at all? Maybe that sort of thing could nudge her back into a more normal sleep cycle, if you're pursuing yours along side her? Probably best to talk to your med therapist about the idea...