so his parents declared him dead?
nice the king can use the fact that they lied to him (the crown) to pressure them and force them to make a vow to never interfer with him again and in 10years their house will either be erased or turn green cause of regret
because noble houses are usualy self contained even a king cant say much regarding how they handle their own affairs but lieing on official records is another thing
(if he wanted to he could use that lie as a basis to investigate them for treason, neat how easy law becomes if certain personages are equal to the country itself)