Hugs to you. I know how you feel, my MIL passed of liver cancer years ago. In the hospital, she had slipped into a coma, and it is THEN that we gave her no fluids at anytime. That only prolongs the inevidable. While she is still conscious, if she wants a drink, she gets a drink!
Usually what happens, is, the pain is sooo great, they keep increasing the morphine until the patient slips into a coma. Then that is when you don't want to prolong the suffering. It is a kindness, really, not to keep administering fluids because the end is near. It only prolongs that for the family, and does not hurt the patient or loved one in any way. By then, they feel nothing.
God bless, and I hope my explanation helps you......I know it is hard!
Take care,
Sharon