With all due respect to the terrible agony these parents are experiencing it is exactly because of their pain and anguish that they should not be deciding what is in the best interests of the child.  Neither should the hospital and doctors.  Balancing the potential harm against the the chance of a successful outcome is never easy - the courts can and do make these decisions and I don't believe the court would pass up an opportunity if it had any realistic chance of providing a meaningful benefit for the child.