Dying from rickets is very unlikely and although possible you have a very small chance of dying from rickets if they are left untreated.
Having rickets usually just means you have a nutritional deficiency which can make it hard for you to grow properly and your bones may become weak and brittle.
Some complications that can arise from rickets are things such as cramps, seizures, and breathing problems.
You can also have an abnormally curved spine and other bone deformities when rickets are left untreated.
Usually rickets is curable as long as you get the proper nutrition and Vitamins and Nutrients that you need and make sure you get enough calcium to keep your bones strong.
You can take calcium supplements and drink milk that contains calcium to help build strong bones.