Dottie
A bone marrow transplant, whether it is your own filtered marrow or a gift from a stranger or friend, does not correct the problem that caused the disease in the first place. The cause is still a personal health problem that will attack the newly planted marrow cells.
The cause of cancer has been known for many years as lack of oxygenation of cells which leaves the body in an acidic condition. The pH can be tested with a saliva pH test. If your dad does not want to go through another BMT it would be wise to start alkalizing and getting lots of useful nutrients.
Good Luck, Dottie