Have you followed the complete process for using Section 88?
- Statement from Doc that driver is indeed fit to drive, for which decision they’ll need to referring to guidelines for medical practioners on assessing fitness to drive
gov.uk/government/publicati … fessionals - you keeping a copy of his application
- sending by recorded delivery, then
- checking for receipt at DVLA end (easily done online)
Be aware that simply having a completed D4 in the post does not mean he’s been assessed as “fit to drive”, doctors do not pass or fail people for a medical, they merely supply the data for the DVLA to make that decision.