TeeS,
The old microlight licence was replaced at the end of July by the new NPPL microlight rating, so anyone training on microlights now will get an NPPL when they qualify.
Adding a SEP rating to the NPPL so that you can fly GA aircraft as well as microlights is very straightforward. You must do at least three hours flying training and take all the JAR theory exams (the microlight ones are slightly different), except the radio ones if you gained the FRTOL during the microlight training.
Beyond the three hours it's up to the discretion of the instructor as to when you're ready to take the skills tests. You have to do two - the Navigation Skills Test and the General Skills Test.
The NPPL SEP rating will let your friend fly GA aircraft up to 2,000Kg in day VFR in the UK only. The NPPL Microlight rating will let him fly a microlight in day VFR in the UK and possibly now in France as well. The BMAA was looking into this.
If you want to upgrade to the full JAR PPL you can do that too, but beware of a catch here. If all your NPPL training was carried out by a JAR flight instructor, at a CAA-registered training facility, then you get a 30-hour credit towards the JAR licence. If the training was carried out by a microlight instructor at an ordinary microlight school then you don't get this concession and will only get a maximum of 10 hours credit for your microlight hours.
Finding a microlight school which is also a registered facility and has JAR instructors may be tricky. There's one at Redhill if your mate is anywhere near that area.
Full details of the NPPL are
here
The governing body for microlighting in the UK is the BMAA,
here