My Lil Sister Is 22 And Works At A Nursing

My lil sister is 22 and works at a nursing home.She has been extremely dehydrated the last week at least.The nursed took her blood levels and it came back at 522., She said she had a 22 oz orange juice,a 16oz Gatorade,And a can of grape soda,the 2 hrs before hand.She says the nurse said those beverages wouldn't shoot it up that high.Im sure it can,seeing those are all high in sugar's.She is scared to sleep because they Said she wouldgo into a diabetic coma.Pls help