Get him to book in a trial lesson at a local flying club if he hasn't done so already. If after that he decides that this is a career he really would like to peruse that hour can be logged as flight training.
I'd go further than that.
A PPL (Private Pilots Licence) is the first step on civil flying training. It's only expensive if you don't compare it to the cost of professional training. All of those hours count to the professional licences later - or it can just be a step to a lifelong hobby and passion.
No young man or woman really knows if they have the aptitude and enthusiasm for professional flying training. But, particularly if they embark on it with that in mind, by the end of the PPL - they will know.
I have some doubts however whether a 21 year old not doing their own research has the enthusiasm, but I may be misreading.
Also, I'd re-iterate, they should be getting a class 1 medical before anything else. Without that, all bets are off for larger professional aeroplane flying - although some other options such as microlight instructor or commercial balloon pilot remain, as do many fascinating non pilot jobs in aviation.