I'm so sorry to hear about your daughter, Anniebach. It must be utterly heartbreaking. 
As others say, hospital-prescribed liquid foods would be a start and I'd hope they will provide you with some guidance. There's also Complan and the like, available from chemists and shops. I'd go carb and fats heavy, so full-fat everything, milk, butter, cheese. Custards and milk puddings are easy to make (if you have a slow cooker, it makes a wonderful rice pudding). Lots of potatoes, bread, biscuits and cakes, too. She might need to eat little and often to begin with, if she is unused to eating full meals - a bit like weaning a baby from a milk diet to solid foods.
My best wishes to you both.