Hi Vanessa,
I'm sure it's not too late! Kids nowadays are always on phones or tablets. Maybe you can introduce him to guitar apps like Anytune or encourage him to watch guitar tutorials on Youtube?
Then when he's a bit older you can consider sites like http://www.bbc.co.uk/learning/subjects/music.shtml and https://www.tutorfair.com to help him develop the skill even more. This could be a great way to help him explore new learning methods. But honestly, all is not lost! It's never too late to get into music.