The Queen is the ruler. He married into the royal family. He was a prince of France or something Therefore her husband cannot be called king because he isn’t blood of the royal family. Only the male ruler can be called King. Prince Charles is the heir. When the queen kicks, he is ruler and will be King Charles.
I think he was from a poor Greek royal family, he couldn't afford to do anything at all but I think she fell in love with him. I think she will step down in a year or so now that he's dead.
Thanks