Treating that child under the NHS in Great Ormond Street Hospital with experimental treatment from the US creates a perverse incentive for the hospital to still allow him to die. It proves them right.
Get him out of there.
Agree who in their right mind would trust that hospital to administer the treatment properly after it is provided? If it “didn’t work” and the baby died they would claim they were right all along and never mention they didn’t comply with proper protocol. Get the baby to a real hospital in the US!