I am the [very great] granddaughter of above mentioned man and am searching for information on his parents, other siblings, wife[s], et cetera.

What I do know:
He inherited the title from his brother Othon in 1240 and had two children named after himself and his brother. His youngest child Humbert became Cardinal Humbert, whose son led the papal army. His eldest child Othon inherited the title, was stripped of it later and became "Othon Villard", then fled to england where the King renamed/retitled him "Henri, Count Willard", whose children then were named with the Willard surname. Henri's great great granddaughter was Margery Willard who married Dolor Davis in East Fairleigh, Kent County, England.