I used my Vitmix to make my mom foods before she passed away. Some of her favorites where smoothie drinks with fresh cantaloupe, raw almonds, carrots and other fruits in seasons especially berries. You can also add yogurt. Presentation means a lot. A smoothie served in a pretty glass with a straw and maybe even an umbrella is more fun then something brown in cup. Also sitting down with them and eating the same food might help. You can also make "gravies/sauces" by blenderizing cooked meat/tomato/potato and then serving over well steamed vegetable and potatoes cubes. Does she like fish?
I personally would not be able to handle Ensure and such. I agree Carnation breakfast would be a better option.