Sorry to hear this Jason. Here's my thoughts...
In my relative ignorance and not being a doctor, I would say your friend should definitely go for the conventional treatment, but there's no harm in trying those complimentary medicines that won't hinder the medical process (and won't expose your loved ones to overcharging predatory charlatans of course). For example, those homeopathy pills are cheap and only water, so while I personally don't believe in it at all I would actually give it a try if I were seriously ill. Acupuncture I expect would at the very least do no harm either.
I know more about the dietary changes that may benefit your friend. The healthiest diet is an Okinawan one, which contains up to 15 portions of fruit/veg a day and lots of seafood. Then there's the Mediterranean one that we're always told about. Whole grains, pulses, nuts, berries, polyunsaturated fats. No processed junk food microwaved in plastic. Going organic can only be a good thing too. Changing to a healthy diet could help psychologically too, because one could then feel like one is taking steps to ensure the best chances for a quick recovery. Treats are nice, so psychologically probably best to keep having them, but they can be 'healthified'- eg premium high cocoa solids organic chocolate instead of the usual cheap crap... or organic milkshake made with organic cocoa powder, etc.
Green tea- up to 3 cups a day for a healthy person (apparently more could slow rate of cell growth down too much hence the 3 cups limit). Tomatoes are GREAT for protecting against cancer I hear, and tinned are just as good, so lots of those. Turmeric 3 times a week is good for longevity in general, although I don't know if it does anything against cancer itself. Exercise is good for the healthy, so one would expect good for the ill too while they can... even thinking about exercise is meant to have a beneficial affect I hear because the body then readies itself for your doing it, whether you actually do so or not!
I believe you're right that the mind can have a great effect on the body's health. I have experienced this in the negative spectrum, so I am sure it works the other way too when you're thinking positively. If I were seriously ill, I would meditate and imagine my body destroying the illness and making me healthy, instructing it. I would imagine myself communing with the energy of the universe and directing this energy into my hands and inside me to help make me halthy again.
As for ayawaska... your friend should probably ask her doctor before drinking it herself, just in case it'll mess with her medication or if the strain on her body could counterract with the medical process somehow. But I see no reason not to get a real shaman over to drink it him/herself and attempt to cure your friend, if such a session were desired.
Remember that stress will not be good for your friend's healing, so whatever she tries shouldn't stress her out.
Support, love and cuddles from loved ones of course (I'm told cuddles make your body release certain chemicals that make you healthy- something dubbed the 'cuddle chemical', beginning with oxy maybe, which is only released during physical contact). Massage?
Laughter! I can imagine it hard to laugh while seriously, but I heard it helps?
I hope all goes well for your friend
