Some previous posts make a good point too. Your son should get an alternative career, or at least an alternative skill and qualification before starting down the airline pilot route.
It always surprises me that many pilots have no other skill or ability, so they end up on a building site or driving a delivery van for pennies after being made redundant from the cockpit.
Just to reinforce what others are saying; don't believe the hype from flight schools. I don't know the exact figures, but out of every 100 students, maybe 30 will get onto the big shiny jets, and maybe 1 will get to be a rich Captain - certainly not all of them.
I would suggest that after passing his Class 1 EASA medical, your son does an aviation related degree, and/or applies to Airbus. He is very young so the actual airline flying can come later, and he will have his tech. career to pay his rent and support his loan for the frozen ATPL, and to fall back back on while waiting for that first pilot job opportunity.