In Kissed, Mary had played with him as she told him, "Sometimes you just need to kick something."
In Left Behind, When the castle is invaded by an Italian count with a grudge against the French King and Queen, Francis offers himself as ransom, while the count accepts he wants Charles and Henry too. Francis protects his brothers and they escape with him through the tunnels.
In For King and Country, due to Mary taking the throne from Francis by becoming engaged to Bash, the line of succession is broken and changed therefore Charles will no longer be in line for the throne and not marry Madeleine.
In Royal Blood, he and his younger brother, Henry III, attend a Frost Fair organized by Sebastian. Where they are supposedly kidnapped but in reality Bash had them sent to Spain for their "safety ". They never made it there because they were in fact kidnapped by Clarissa on their way. She threatened to harm them since Catherine cared for them more than her.
Due to later events in the series when Mary chose to Francis instead of Bash, Francis was restored as the Dauphin and the line of succession is back to normal.