I'm pretty sure they don't go in for coronations, still less anointings -- they still think of knightings as foreign folly, you're a knight because you fight -- but they have to do something, because I have to have something where the main character is declared king over his younger half-brothers.
Their mother minds. I have to decide whether her belief that her higher birth -- and she does come from much higher stock than the main character's mother -- means her sons are more fit is a curiosity or a serious consideration for others. I know that there were times in Chinese history where polygamy complicated the succession because the son of a woman of higher birth is obviously more fit than one from a lower-ranking wife. The Byzantine belief that a son born after his father became the emperor -- a porphyrogenitus, born to the purple -- has a superior claim is kinda moot since his father was king when he was born. And both cultures would probably be regarded as rather decadent by this kingdom.
I think they may hail him. I know some Scandinavian kings were chosen among all the dead king's sons that way, and my main character has the advantage of age.