Hi, Venkat
In addition to the the liquid nutrition (which my husband hated), I made him protein shakes with whey power, Carnation Breakfast Essential powder, and various milks - rice milk, soy milk and cows milk. Typically, I would do dairy-based in the morning, then call him at work and nag him to drink a couple of Ensures, and then soy-based at night. I also added fruit to the mix - peaches were the easiest at first, then pears, prune juice and bananas for variety. We also had some monumental failures, but that's the way it goes. My guess is that Eshwar has made some very good suggestions - the Ghee in particular with help with the calories.
Now - about your mom. If she is able to make something you can swallow to keep you going, is will make her feel happy. Make sure that you give her enough information that she can help you; try to get across to her, though, that your tolerance for various foods will changing for a while, and sometimes things just don't work.