The Rev. Franklin Graham announced that his aunt and the only surviving sibling of his legendary father, the Rev. Billy Graham, died Thursday morning. Jean Graham Ford died at the age of 91, Franklin Graham announced in a lengthy tribute to his beloved aunt on his Facebook page. Franklin Graham said like him and his father, his Aunt Jean was devout in her faith. “My Aunt Jean loved the Lord Jesus Christ, her family, her church and the work of God’s people around the world,” Franklin Graham wrote. “She, along with her husband Dr. Leighton Ford, was always a great encourager to my father through…