Try a different approach. Cancer cells are quite immunogenic, so they're easy to kill, but their fickleness isn't what matters. It's their environment (TME: tumour micro-environment, if you want to search the literature) and their evasiveness that makes treatment hard. And maybe you can't do anything about the cells themselves, but you can certainly affect the TME.

Since you have biopsies, find the targets of the specific cell line in question, and research what you can do against them. Ignore the advice that tells you nothing is relevant because it's impossible to reach cytotoxic levels of some compound you're researching in one's system. You don't need chemo-level cytotoxicity. You're nudging the environment in the right direction, not aiming for a response the next day. Consistency wins the day. And that device reeks of scientific reductionism, and ignores things like metabolites, your microbiome, and so on. People in particular downplay the microbiome which seems to be directly involved in the immune system. You need to feed those buggers. For example, it's now established science that those without akkermansia do not respond to immunotherapies like PD-1 inhibitors. How do you get akkermansia? Ellagitannins. Walnuts, pomegranates, etc.

NF-κB is an example of a target. It seems to be involved in most, if not all TMEs. The great news is that plenty of things can downregulate NF-κB. For example, exercise (non-negotiable, the best medicine, if your wife can do any), berry anthocyanins, and even omega 3 DHA and EPA. The latter is in particular interesting because omega 3 is needed in inflammation resolution, and directly affects NF-κB. Anyway, find the appropriate targets, and do what you can do move them.

My other piece of advice is to make sure there are no deficiencies. Do the blood work. Make sure vitamin D levels are up there (they modulate the gut microbiome and immune system), omega 3 index (not free plasma, but the one that measures the actual weight taken up by cells, it's a more expensive test) aim for 8%, and so on. Sun exposure (not for the vitamin D, but also that) is also great for mitophagy. There are studies showing that cancer patients with sun exposure have better survival outcomes than those that don't get any sun.

Sorry you have to go through this. I pray that you and your wife, and everyone else involved have the strength and wisdom to get through this.