Thank you for the replies.
Okay, I feel kind of stupid now. After reading the obit and on the drive home yesterday, I realized I have met Stephen's grandmother and father.
My friend that lives across the street from them has always told me that there was boy with DMD across from them. I never had the opportunity to meet him and never questioned that he had DMD. Well, back in August, my husband and I had dinner at his grandmother's restuarant (his dad is the head chef). We saw that they were going to be hosting an event to raise money for MDA and asked them about it. Debby told us of her 13 year old grandson. He had Pompe, not DMD.
I had no idea that they were the family living across from my friend until yesterday. I'm sorry if I caused any undue grief for everyone who's heard of this. I was just going by the information my friend had given me. It is still a horrible and sad passing, but now that kind of explains his age and difficulties.