My Mom Has CHF And In A Rehab Facility. They

My mom has CHF and in a rehab facility. They sent her to the ER Monday morning because she could not wake up. CT scan, chest X-ray, blood test and urine test normal. On Tuesday and Wednesday she could hardly hold her eyes open and today (Thursday) we could not wake her up. She also has chronic UTI's. She woke up his evening and was hungry. She goes through these cycles constantly. What causes the sleeping and why does she keep the UTI's?