Annelisle there is no guarantee that your nephew will become a professional soccer player if he engages in specific training techniques for soccer. The most important aspect to master any sport is understanding and perfecting the basics. And even if you have player that has achieved that it is still no guarantee.
The best training techniques for soccer would be the support you can give him for fulfilling his dream. Reason As a player you might look awesome during practice but when you are on the field participating in an actual game it is totally different. There are a lot of things you have to take into consideration in order for you to fine tune your game and these include 1.
Skill 2. Footballing IQ 3. Teamwork (playing for the team and not your self) 4.
Listening,understanding and carrying out the coaches instructions 6. Strength when holding the ball 7. Stamina 8.
Health etc I think the young man is on the right track you stated that he practice a lot on his own and that is good. You also stated that he is member of a high school team that is excellent. Practical experience is always the key to sports and by being a member he will get that.
What I would advise is that he study the game. Get books and watch videos or past and present games. Watch how the professional players play and approach the game and look to mimic them.
Also it would be ideal for him to find out wich position he best suited for. Example if he is very skillful he might be best suited for a midfield attacking role If he can limit the play of the opposition he would be best suited for being a defender If he has a keen eye for scoring goals a striker Some people are born with talents and from a tender age they progress at it and become famous for their exploits of the talent. Others although not that talented at birth due to hard work and perseverance they excel at the talent.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.