There is no way you can prevent appendix. I heard a lot of tales like: in no case swallow the husks of seeds, watermelon seeds, melon seeds, etc. Moreover, I consider this heredity: on the maternal side, all women suffered this, my father and his brothers did not have it. Also with his wife. Believe it or not.
The answer to both of your questions is: nothing. To date, there are no preventive measures for acute appendicitis. And if the doctor has a suspicion of the presence of acute appendicitis in a patient, then the only treatment is surgery. No alternatives are provided. And by and large, there are no contraindications to the operation.