Wheelchair/mobile bed. In hospital efficency

Here's a idea for Doctors, Doctors need to tell elderly people to drink more.

I care for my elderly parents and I have seen so many times symptoms and medical issues. Its hard to get them to drink the right amount of water each day but when they do, you can see a huge improvement.
  But when you most see the improvement is when they end up in hospital from a bladder infection or just run down and not making sense and nearly all the time they put either of my parents straight on fluids and within a hour or so there saying to me  what am I doing in...