Hi Fernanado!
It should not persuade anyone to do something they do not want. Thus, a person has to realize that if he wants to do it or not, regardless of age. Of course you can explain to him how the SFI business and show by their example. We all have important additional income so he can propose to try, because the membership, support and lessons are free, so I let him decide.
I wish you much success in your work!
