Freezing is a not bad idea and can be a very good way to preserve the nutritional value of many vegetables. As long as they are high-quality (organically grown for example) and were fairly fresh at the time of freezing, the overall nutrient retention in frozen vegetables can be quite high. However, if it's possible, you can definitely make a large batch of broth ahead and freeze for later! This is a great way to continue healthful eating when you are strapped for time.
Disclaimer: The Gabriel Method is not intended to treat, cure, or prevent any disease or illness. This information is intended for educational purposes only, not as medical advice. Always check with your doctor before changing your diet, eating, or health program.