If she is unable to drink more water. Give her gud (jaggery) after meals that will help her retain body fluids and do encourage her to eat fruits like watermelon, apple, guava, grapes, oranges and sweet lime, etc as these contain water and electrolytes. Give her glass of milk or butter before bed. Also include a handful of nuts in her daily routine. For perfect diet and menu planning according to her body situation, consult dietician. Any other queries or want to have appointment message me personally.