Hi Morgan, I can imagine how scary this is for you and your mom. Good news is that standard chemotherapies (for example, FOLFOX and FOLFIRI combinations) can do wonders in reducing the size of tumors and in keeping your mom around longer. Some people have such extreme response that they are initially never expected to be operable, but chemo shrinks the tumors enough that they later can be.
I'm a stage IV inoperable colon cancer patient myself, living with CRC for 2.5 years. One thing I'd recommend looking into (with her oncologist and/or Google) is an HAI (hepatic arterial infusion) pump, which gives concentrated chemo directly to the liver. This can be very effective for treatment of CRC patients whose metastasized tumors are limited to the liver. It certainly has worked wonders for me in keeping my numerous liver tumors stable. Unfortunately HAI is only done in a few cancer centers in the world - most notably Memorial Sloan Kettering in New York City, where it was pioneered by Dr. Kemeny.
Other than looking into HAI, here are a few other suggestions:
Educate yourself/herself about colon cancer and its standard treatments (this board is a good place to start; there are a few others too), and get a second opinion about treatment and outlooks - preferably from an NCI-rated center.
Exercise as much as possible - even just a short walk several times a week if that's all she can manage. This helps reduce inflammation and stabilize insulin levels, and some studies show it can help cancer patients fare better with both treatment effectiveness and reduced chemo side effects. Plus it can improve both mood and energy levels.
Try to cut down on foods with lots of added sugar (e.g. soda, candy, sweets). This is a slightly controversial recommendation, but I've heard enough evidence to be convinced that this can reduce tumor growth factors in the blood (e.g. IGF-1). And try to eat more natural (i.e. less-processed) food, esp. fruit and veggies.
Have her doctor check out her Vitamin D blood level. Upwards of 80% of cancer patients have too-low levels of Vitamin D, and studies show that those with higher levels of D fare better on treatment.
She will doubtless hear numerous recommendations of "miracle cures"...please take these with a grain of salt. Even though the people recommending them are well-meaning, many of these panaceas are ineffective, or worse, counterproductive. I'd recommend Googling "MSKCC herbs" for a link to their amazing database with pro/con evidence for many natural agents that are reputed to fight cancer.
Anyway, best of luck to you and your mom in this incredibly tough time. You're just a few weeks in, and still in the shock stage. Believe it or not, it does get much easier to cope with over time.
-Chip