Guys,
It's not 70k for just any old course but rather a bond for a sponsorship (I'm assuming it is the CTC one). You are pretty much guaranteed a job at the end with a major UK airline at the end who will make payments to your son to cover the bond repayments to the bank (at current rates you actually make a few grand over the 7 years).
There is also the insurance that if your son does not make it then he will only be liable for up to a maximum of half the bond and thats only if he drops out in the latter, more expensive stages of the training.
The best thing to do is have a good read through his contract before he signs it or better still ask the questions at the meet and greet. You will get the answers you are looking for.
Apologies if it aint the CTC one and I've just been rambling on!