Not much help I can offer you. But how is your Gradma's health apart from the 子宮? If her health is fine, I think it's not a big problem. On the other hand the doctor will help her perform a full body chech-up beforehand to ensure she is suitable for operation. Actually 70 age is not that old. If she's physically healthy she should be able to recover quite fast too. Trust the doctor and don't worry.