To prevent osteoporosis, ensure that elderly family members get enough calcium and vitamin D. This can be achieved by consuming calcium-rich foods like milk, yogurt, cheese, and leafy green vegetables, as well as getting sunlight or taking vitamin D supplements. Additionally, encourage them to engage in moderate exercise such as walking and light weight training to strengthen their bones. Avoiding smoking and limiting alcohol intake are also crucial because they can affect bone health. Lastly, regular bone density check-ups can help detect issues early and allow for timely intervention.