Ok here is my two bobs worth.
I started my flying in 1972 with a PPL. Went to the USA to get a licence (cost £3000) and then onto bush flying in Africa. When I had enough hours (1500 then) got a British licence, did some charter flying and got a job with Dan Air in Aberdeen. Progresed up the ladder and became a 727 Captain with them. Was sent to Australia and joined Ansett ending with them as a check and training Captain and flying a 767 on long haul.
Many of my friends have been killed bush flying. Both the airlines I worked for went bust (no retirement benefits, little pension) my health suffered and I failed my medical. Went into training industry and met many unsavory crooks.
However it was a great lifestyle and I have seen most of the world and stayed in most of the best hotels in the world.
Would I do it again with hindsight NO.
The industry has changed. Automation has made the job very boring. T&C's are bad at the bottom and getting worse. Competition for the few jobs available is intense.
If your son is adamant that he wants to do it, then he must get himself on a course where someone else is paying for it and there is a guaranteed job at the end. Do not under any circumstances get yourself into huge debt unless you a very wealthy and can afford to write off £100k plus.