User blog comment:Omega natsu2/Chapter 354: Ephialtes, Predictions./@comment-117.227.65.46-20130928131700/@comment-4829046-20130928132930

I think the point here is that Gray And Silver have many parallels. Even though those parallels don't really mean that they are related. Especially since Gray learned Ice Magic AFTER his parents supposedly died, this theory doesn't seem that possible unless Mashima was just being lazy and decided to go with the "convenient" route.