My Husband Had A Allogeneic Stem Cell Transpalnt For AML.

My husband had a allogeneic stem cell transpalnt for AML. He is 4.5 years out and is on immunosuppressants. As of 3 weeks ago he had extreme fatigue (sleeping most of the day), no appetite, weight loss, temporal head ache and low grade fever. He has had a lumbar puncture, brain MRI, CT scan of torso, bronchoscopy, blood & urine cultures, ultrasound of kidneys & bladder, EEG & EKG. None of his doctors, neurologist, BMT, infectious disease, pulmonologist, can get a diagnosis. I am very concerned.