I always love stories like these because they tug deep inside the soul. Your step-child seems somewhat similar to the problems I had faced.

I was a golden child going to top universities and in with the national golf team. I went off the rails though. Stopped going to school and sold my golf clubs for a couple of bags of weed.

I can trace it all back to not having stability. My mum's partner died and my own father was of no use. If I hadn't sought help on my own I'd probably be in a grave by now :)

Long story short - be thankful that you did what you can because he'll look back on that in times of self comfort.