The boy had a rare illness called Common Variable Immune Deficiency (CVID), a disorder characterized by defective B cell function leading to impaired immunoglobulin production. Because of this, his body couldn’t fight infections well, and his lungs were badly damaged. He needed special monthly treatments just to stay alive. The only real chance for him to get better was a Bone Marrow Transplant (BMT), which is a difficult and risky operation. Miraculously, his sister was a perfect match to donate stem cells — something very rare. With bravery beyond her age, she gave her stem cells to her brother, showing the true meaning of Raksha Bandhan — love, protection, and selfless care.