Really great to hear that you could do all this as a family "ilvaporista". I certainly wish my parents had gone "all in" like that too. I also started early. I must have logget thousands of hours in flight sims, spent hundreds of Euros on RC planes and even more as a gliderpilot. (also funded by myself from I was 15). Although I had no money handed to me directly from my parents, I had their full support and I remember my dad driving me 45km each way for years to and from the gliding club before I had my drivers license. I have also more than once had to ask for money for food back when I worked for the harpe many years ago in the beginning! I am truly grateful that they chose to kindle my interest of flying from day 1.
I think your son has the drive to become an excellent pilot from what you describe, and with that level of commitment I think he is pretty likely to succeed.
With regards to the lucky cadets who have had everything funded by mom and dad, I did notice quite a difference in the level of commitment back when I was working as a FI. The guys who had to go the extra mile themselves did tend to be more hard working, dedicated and succesfull - Even though the natural abilities was lower in some cases.