Avemar and Cellect are both very highly regarded products and I see no reason why they cannot be used together. The Budwig flaxseed/cottage cheese combo is simply outstanding and has a long track record of success. I will also mention that supplemental oleander extract might be well worth considering. Besides being a tremendous immune stimulator and cancer fighter, it also either lessens of eliminates virtually all known chemo side effects (with the exception of hair loss when the chemo drug is cisplatin).
Interestingly, my research into cancer alternative and choosing the best items I could find for an all around anti-cancer protocol resulted in me ending up with virtually every item contained in the Cellect product before I ever saw the ingredients in the product. So, yes, I would consider it a very good product. Neither it nor Avemar are inexpensive, but nevertheless highly regarded.
Whatever supplements you decide on, please realize that beating cancer and keeping it at bay involves a lot more than just what you take to eliminate the symptoms (tumors) of cancer. For the best chances of success one should incorporate an entire anti-cancer lifestyle which, in addition to key supplements, should include diet, lifestyle, stress management and more. See, for example:
http://curezone.com/forums/fm.asp?i=1780697
and
http://curezone.com/forums/fm.asp?i=1777634#i
I wish you and your mother all the very best.