What could be wrong with my Grandmother?

My grandma once randomly passed out on the kitchen floor (I'm not sure how long ago this was, she only mentioned it to me and my family recently.) About 2 days ago, she was saying that she wasn't feeling well and had a fever. When my aunt went over to her house to check on her (knowing she wasn't feeling well) she saw my grandma lying on the floor with blood all over the place. My aunt called the ambulance and they rushed her to the ER. From there, they found out that she had bleeding on the brain. (When she fell, she hit her head pretty badly.) The bleeding on the brain finally stopped on its own and the Dr. said that should absorb, so that was a good thing. Then my grandma passed out again when she was in the hospital. (For causes unknown.) She also seems very confused and is hallucinating. (Claiming she sees bugs on the ceiling in the hospital when the lights are turned off.) She took blood work and her blood counts are way off. She is 87 years old and has been healthy up until lately. What could be wrong with her?