No mother would allow a 7yo to dye their hair. No one. Much less one who spends all her spare cash in drugs.
I talk from experience. Well, not about the drug part. But about the dying in order to not stand out and be picked part. The only case I could see Jason dyeing his hair black it coould be if Catherine moved him from one scoot to other where noone would pick on him because they disn't know him. Which, eh, I don't think it happened at all. And then, she whould have to dye his hair regularly because the roots show fast.
Yep, I don't see it.
He is natural blackhaired until another writer wants to change it again.