As you probably already know, keeping her as comfortable as possible is key - so looking to see what symptoms she is experiencing and then choosing lifestyle options, including foods/diet, to help alleviate those.
Here's a good general website Fact Sheet: http://www.ninds.nih.gov/disorders/amyotrophiclateralsclerosis/detail_ALS.htm
A study (done on mice, not humans) shows that a low-carb; higher fat diet may help slow the disease (http://www.webmd.com/diet/news/20060421/diet-slow-lou-gehrigs-disease). In addition, discuss w/ her Dr. protein requirements to help preserve any lean muscle mass. Higher protein options for the NutriBullet could be protein powders, nuts, seeds, beans, nut butters, cooked quinoa (gluten-free!)
In addition, bright colorful fruits and veggies won't hurt according to this study here: http://www.medicalnewstoday.com/articles/255513.php