Apprecaite your points. But, from my experience, the only way to teach your son is through his heart. Be little diplomatic. sons normally like mothers’ diplomacy. or they love it.
Find examples from the areas of interest he has(or the topics he is interested in). Many parents buy products like Espoir’s "Smarten Your English through Cricket", "Smarten Your English through Movies" etc. These products groom your son to become a super hero one day. They have the magic to mix English, personalithy development, communication skills with Cricket.
I searched all over the Internet including Amazon.com. Whenever I travel abroad, I ask for similar products in foreign book stalls. Nobody has similar products, congratulations Espoir for your copyrighted, unique products.
The company has other products like "Smarten Your English through Success Secrets", "Smarten Your English through Movies", "Smarten Your ENglish through Love & Romance", "Smarten Your Communication through WIt & Wisdom" etc.
Just try it.
Jai Ho.