NHS guidance given to GPs for aftercare post USA operation

A person needs surgery only available in USA because UK doctors do not do it. After the operation can UK doctors refuse to help with aftercare in the UK, is there any NHS guidance/protocol to Doctors in respect of this issue, will they prescribe drugs for aftercare

GP's in the UK would not refuse medical treatment if needed and would not refuse to prescribe medication if needed. They might want support from a UK consultant in complex cases, though this should be availbale on the NHS (often quicker to go private though)