At one point, Barbara contracted the demon pox disease from her husband, Benedict. Horrified and ashamed, Barbara committed suicide by slitting her wrists in 1863. To cover up the true nature of her suicide, Benedict told everyone that she died of grief after her own brother, Silas', suicide, but the key to the truth remained in the report of her death in the Silent City.
Despite having died while her children were still young, her eldest, Gideon, who was five at the time of her death, missed her and longed for her. Gabriel, on the other hand, barely remembered her; however, this did not stop him from believing his father's story and partly blaming the Fairchild family, particularly Granville Fairchild, a good friend of Silas who was accused by Benedict as the one who indirectly led to Silas' suicide, and, thus, Barbara's death.
Gideon never fully believed or understood Benedict's story. Thus, when Jem Carstairs found out in 1878 that Barbara died with a shield-shaped rash on her left shoulder, a fact that was on the report of her death kept in the Silent City, Gideon was much more open to believing the truth than his younger siblings were. The truth had since become public knowledge, particularly after Benedict's own demise.
Before her death, Barbara was said to be tall and slender, and had curling, sandy brown hair and green eyes—physical attributes her children inherited.
- Her granddaughter, Gideon's daughter Barbara Lightwood, was presumably named after her.