Mack played Hilltop Colony resident Abby in five episodes of season nine of The Walking Dead. She also appeared in Chicago Med and 9-1-1, among other shows.
The actress and producer died of glioma of the central nervous system.
“She would want you all to know how much she loves you. And as her sister, I want you all to know how brave that tough SOB was, especially when she decided to make the leap to be reunited with God,” her sister wrote on Instagram.
Back in March, Mack posted an update with a short video of herself ringing the bell at the medical centre, signalling she had finished her proton radiation treatment.
“Overall, this journey has not been easy, but things are getting better – improvements are tough to see when you’re in the thick of it,” the actress wrote at the time.
