Student or Learner
I think that who here refers to people/ volunteers who work at King Kahalid Charitable Foundation. As a result, it followed by a plural verb- describe. Am I correct, please?The campaign aims to "provide legal protection for women and children from abuse in Saudi Arabia" and is endorsed by the King Kahalid Charitable Foundation, who describe "the phenomenon of battered women in Saudi Arabia" as "much greater than expected".
Saudi Arabia cabinet passes ban on domestic violence
Americans usually use the singular for an organization. You'll find the plural used more often for organizations in the UK than you will in the US.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.