Het means that they have one copy of the hypo gene, there needs to be two copies in order for hypo to visually show. Your guy got one copy from each parent so he shows the trait.
He almost looks like a pastel too which simply means he will have softer pastel colors and not the bright, vivid ones. Hypo pastels are very pretty and I would guess you guy will be yellow with orange.
Also, you guy isn't a trans, they are gummy looking as babies. Kinda icky actually.