He will be classed as a PEP no doubt but that doesn’t stop a bank on boarding him.
He will be subject to enhanced due diligence rather than standard, particularly on source of wealth and source of funds pre onboarding and will be subject to closer scrutiny and ongoing monitoring.
At anytime...
He may no longer meet their risk appetite, they are not obliged to get into specifics
He of course can take it up with the FOS if he’s unhappy with their final response.