Encourage him to get a worthwhile university degree and become employable in another activity. Then he'll be in a position to pay for his own flying training
Not always a viable option for some people.
University
and flight training? That's got to be racking up the sterling!
It's a good idea if you can afford it, but personally I wouldn't want to be studying/training towards the ATPLs etc with the additional stress of a student loan hanging over my head. Of course you could wait until you've saved up the money from working in your university graduate job, paid off said loan and go from there, but it's likely by this point age is starting to show a wry smile.
There's no way I'm saying age is not on your side in your late twenties/thirties! What I'm saying is that for somebody with the dream to fly from an early age, I believe it's possible to break into this industry a lot younger than that.