This might sound odd, but in addition to all the wonderful positive things you are doing, give her time and space to experience sadness, grief, loss, anger.
Try to avoid giving her the idea that she is letting all of you down if she has a bad day or even a couple of them. Part of her healing will come from feeling all of her feelings, not just the hopeful, uplifting ones.
Let her know that she can call on at least some of you when she wants to complain or just be sad, and that you will listen without trying to talk her out of her down time.
Give her permission to be honest and not have to "take care of the caretakers." She will probably already be doing some of that with her parents, and it's an exhausting job.
The best thing you can do is listen. The second best thing you can do is share your self. Don't stifle your own voice because you feel guilty that you're not sick. Tell her that she has the freedom to say what she wants and to talk about anything and everything. And, within reason, you live by that, too. There are few things more depressing than walking around on eggshells or feeling that others are doing so for you.
On a day when she feels strong, help her to make a list of practical favors she can call in. Picking up meds or dry cleaning. Making a pot of soup. Bringing inexpensive flowers. Cleaning her bathroom. A whole menu for her and others to choose from when they say, "Call me if you need anything." Invariably, you can't come up with anything when you're put on the spot like that, but if you have a list ready, it can be helpful to everyone involved.
Make her a basket that contains phone numbers and addresses of friends, the stores she frequents, restaurant menus, the other places she does business with. Include note cards, pen, stamps. Ask her if she needs to send birthday cards or notes for other occasions. It's so hard to gather these things together when you feel bad, but if they are right at hand, you can spend just a little energy and feel like you have accomplished something, and you aren't totally out of touch with your old life.
Find out if there are certain magazines she likes or hobbies or interests that might have some kind of publication. If she's like the rest of us, there is never enough time to sit and savor that kind of reading. Stop by the library and pick up some back issues of two or three different magazines and let her know you'll pick them up and return them when they're due.
Give her small bottles of light scent. Peppermint sometimes helps with nausea. A little spritz on herself or her pillow can help her feel attractive when she isn't looking her best.
Ask her what she wants. And doesn't want. Some sick people don't want to hear what's going on in the world around them. Others hunger after the details and live through them.
Rent a video and watch it with her.
Get her some books by Anne Lamott.
Hug her again.
She is very blessed to have such caring friends.