Hello, My Mother Is Suffering From Anemia. She Was Given

Hello, my mother is suffering from anemia. She was given 4 units of blood 2 weeks ago when she entered the hospital with a hemoglobin level of 5.6. She had a colonoscopy and endoscope performed without finding anything wrong. When she was discharged from the hospital, her hemoglobin level was 9.6. Now, just 2 weeks later, it is 5.9, with no obvious sign of blood loss. She's having trouble breathing again. She is 83 years old.