problems with Brain Cancer

My Mom had lung cancer and it recently spread to her brain in 3 seperate spots.  They put her on dexamethazone (sp?) and pain killers and then performed full-brain radiation.  Since then they have been trying to wheen her off of the steroids and as she reduces down to 2mg a day (1mg in the am & 1 in the pm) she starts to get her headaches back.  Recently she was taken to our local ER because she was having sever headaches and had been vomitting all day.  The doctors gave her a couple milligrams of the steriod again and morphine for the pain.  My mother was obviously dehydrated as well, but the doctors did not give her any fluids.  I asked the ER doc why and he simply said "we just don't do that".  I use to work on an ambulance and was never told not to give an IV to someone who was dehydrated and also had brain cancer.  So I asked the ER doc again and he mummbled something off to me and from what I got out of it he said "we don't give people who aer dehydrated and who have brain cancer fluids because they don't react the same way people who don't have brain cancer do."  So I'm confused.  Why not give my Mom fluids to treat the dehydration?

[Connie 1]

maybe they're worried about the brain swelling?  dunno.