10 out of 10 for Luke's advice. Get little Johnny to do some of the leg work first. If he can get his private pilots license over the next few years without resorting to his parents cheque book, then it will probably be a good bet to fund the rest of his flying training.
As a start, next year he will be able to apply for a flying scholarship.
Air Cadets - Flying scholarships
Scholarships
Flying Scholarships 2010 - GAPAN
Even if he is not successful in getting Betty to pay for a few hours of his training, the aptitude tests that he will complete will give a good idea of his potential to pass the course.
Good luck