He didn't notify most of the people even the family members, he had the Powers and authority to do anything, he was in charge of the Royal family after his father had stepped down and accepted him to take charge, but since he had matters of the Country to govern, he let his father continue being the King and continue taking care of the Royal family matters while he occupied the Presidential seat.
Currently, he wasn't present and thus, he didn't need to worry about anything as he had traveled because of some Congress, and his mother? He doesn't even know her or where she ever came from. He didn't know if she was alive or dead as his father never talked about her.
Every time he had inquired about his mother, he could see pain and anguish in his father's eyes, and to see him paining over and over because of that matter, he had decided to let go and never inquired about her again.