Have you played to update? That would never happen for pretty obvious reasons not just the fact of previous bad blood between them, theres the fact hyosuke says the prince is just a sex object and if he was his kingsguard he would just fuck him and ditch him if he was in danger because its stupid to die for someone els. Then you have what happens at koshiro's village.
Just no, if anything happens with hyosuke it's most likely going to be in the corruption route.