I,too, am a self taught player times 40 years.I lean towards the belief that if they want to learn bad enough they will on their own. My oldest 2 wanted to play so I invested in the appropriate equipment and leasons just to have it all pawned (without my knowledge) within 2 years.
I bought my first guitar....on my own..at 10 and was playing in bars by the time i was 14. My parents didn`t force me to learn any specific way nor did they hinder my no doubt attrocious practicing which included a basement band for 7 years.
I would say give them the basics in chords, let them choose their favorite music and play till their fingers fall off.
Gary