The reasoning has to do with what the court/government perceive as a bigger issue which is the failure of the NHS. They cannot let this or any child go elsewhere for care as it will show the failure of their socialist system/government. They must protect their own no matter how many children/families must suffer. The only way this changes is for the good people of Britan to stand up for themselves.
A cynical part of me thinks there’s a financial piece too. It’s going to be too expensive to pull him through and support him, keep him living. It sets a precedent. Some bean counter just got a say in Alphie’s medical decisions.