I have had some people tell me that the Norwalk is very difficul to use and can be quite messy. I think that a masticating juice is better, and much cheaper.
Also, you can not set yourself up to be the blame if mum does not make it. Do your best, and have peace knowing that you did what you could. Most cancer patients are scared and alone, and treated with complete emotional detachment from both Dr's & family/friends. Your mum is quite fortunate that you are willing to make this difficult walk with her.