blandford50;
Congratulations on your son's acheivement. However, his EFT graduation is not 'Wings'; those come after AFT. To obtain his PPL, he'll need to pass the theory exams and to fly the 'qualifying cross-country' in order to gain the relevant course completion certificate from HQ EFT which will credit all his EFT flying for PPL issue. The EFT staff should be well aware of these requirements.
However, if he's no longer on the UAS, his flying experience will still count. He'll have to pass all the theory exams, fly the qualifying cross-country and also confirm that all the relevant JAR-FCL flight requirements have been met before flying the PPL Skill Test on a civil SEP aeroplane.