yes, a pastel sibling might be a great looking normal, but it is a normal. You can breed it all year long to normals, and you get more normals. It is that strange co-dom gene thing.
Pastel siblings are normall very pretty snakes, just normals, as most breeders will use relaly nice females to breed to their pastel males.
I got several pastel siblings early in my snakey experiance, and was told they MIGHT give me a pastel, and I bought that line of blooey. That is what I get for not researching the morphs before buying. I ended up trading them as normals for a couple normal hatchling females. In other words, 3 of my pastel sibling males, for 1 normal hatchling female.
If you like the looks and want it as a really pretty snake, go for it, and he might make some very nice looking normals, if you were to use him as breeder.
Wolfy