I need to get more fluids into my wife (70)with aphasia but she's not drinking water like she used to?

Sugarless popsicles.

Try some Pedialyte or Gatorade. She needs electrolytes, more than just plain water. In a small glass of water you could add a pinch of salt, a pinch of sugar, and a pinch of baking soda instead of plain water.

Hot and cold (fruit) soups, fruits, foods with high water or fluid (not sugary) content. Some people will recommend popsicles, which are tasty but also sugary.