Hi Tim,
Firstly, refreshing, and wise, to see a parent asking the questions on here, seeing as more often it's the poor parents faced with the financing.
The whole flying training thing can indeed seem to be a bit of a minefield.
Basically, I can give you the general run-through of obtaining the licence needed to qualify your son to then attempt to get a commercial flying job. However the costs of which have probably changed since my day (about 7 years ago) but I'm sure others here who are more recently through the training stages can give you up to date costs.
I'm assuming here that your son will be doing the modular route through training given the financial climate, as opposed to integrated.
Basically the difference is modular you can choose different training organisations to do different bits of the training, you can control the timing more to suit you, and it generally works out considerably cheaper than integrated. Integrated means you do a course with one organisation, all the way to fully qualified CPL/IR holder (the licenses needed for airline flying if you like), it takes a shorter time, but is more expensive. Voila. In a nutshell.
(Note to the integrated versus modular brigade. DO NOT turn this thread into a slanging match, this is about helping a parent understand the route through and help decide about his son's future, not a bun fight).
Sorry about that, where were we...
The way I went through the "system" was almost as cheaply as I could have at the time and it was as follows. First off, Class One medical at Gatwick to make sure I had two arms, two legs, and can cough nice and loudly. 400 quid for the priviledge thereof.
1. PPL
2. ATPL groundschool with Bristol Groundschool, distance learning. This allowed me to maintain my full time job whilst studying the enjoyable light reading material in the evenings and weekends. Took me just over a year to finish this little lot. Bristol are really very good, other schools also do similar, and I believe are also very good, just that I chose Bristol and can honestly say they were excellent. Think it was about two grand for it.
3. Then I went to Florida to do 100 hours flying, hour building as it's called. I Think that worked out at about $40 an hour to rent a plane for a 100 hour block. Roughly anyway.
4. Came back to Blighty then to enrol on a Commercial Pilots Licence course at Stapleford in Essex. This was 25 hours (Im think, it's been a while), and about £4000, £4500 quid, again, roughly.
5. Multi engine rating and Instrument Rating, again at Stapleford. About £1800/£2000, and £10000/£11000 (ouch!) respectively.
6. An MCC course, Multi Crew Co-operation. Did this at Wolverhampton, 2 week course, £2000.
And tadaaaaaaa, hey presto, qualified pilot, CPL/IR and MCC.
As said earlier, that is a typical way through the modular route. Your son could do integrated (ie a course taking just over a year at one particular school) but that will be more expensive and the timing of it right now ain't too advantageous. However I will say to placate some people that I know the quality of these courses is normally very good, however my own personal opinion is that it was better to get the licences done a bit cheaper and in my own time. It suited me to do modular, it doesn't suit everyone however.
Hope this helps Tim. Good luck to your lad.