My husband was 69 at the time of his diagnosis for MDS and after his first round of chemo one doctor told him he wouldn’t be a candidate for the SCT but like your husband he has always worked out. Our hosp had just started a program where they have the patient do Physical therapy to regain their strength. He was one of the first ones and he did get strong enough for the transplant and is 2 yrs out. So even if he is tired and can ask the doctors for a physical therapy referral. In the beginning he was using a walker and hasn’t used a walker since transplant. One day at a time.