Hi Lewis,
It sounds like both you and your wife are having a tough time of it, especially if Michelle is in pain :-( However, you are taking the steps to reach out and ask for help, so I think that is the first point.
In addition to Tania, Karen and Janet's suggestions to take Michelle to her GP - can I also suggest that you give Cancer Council a call on 13 11 20 (it's free and confidential) and there telephone information and support line is supported by specially trained nurses who can give you tips on how to move forward and offer emotional or practical support for you both.
I hope this give you some ideas of how to get support for both you and Michelle.
Best wishes, Daina