The King's Guards with the color draped in black means the 'King or Ruler' has died but is he or...

This video of the King's Guards with the color draped in black.. We find out later Lord Jacob Rothschild is dead.. Who really runs this country? The parade of the 'Royal British Cavalry' has a special message.. The custom of royal riders is to never bring a white horse without the presence of the king and queen.. The presence of a white horse means the presence of the king.
When King Charles is not present in this Cavalry.. it means that he is dead..But was this really meant for Lord Jacob Rothschild instead? Lord Jacob Rothschild being the real Ruler of England and the Royal family are only the mere puppets?