Every person needs a living will. Without a living will, you will be at risk of starving or having not oxygen until you die. A living will is very important because it says what you want when you cannot speak for yourself.
A Catholic living will is a legal document stating your desires of how you want to be cared for if you become not capable of making decisions due to illness or brain damage. Without a living will, you are at the mercy of your next of kin and/or medical staff.
In your Roman Catholic living will, you state that you want to be in accordance with the Roman Catholic Church. The Catholic living will says you want to live under ordinary means such as nutrition and hydration. The Catholic living will also makes clear that you do not believe in euthanasia, but you don't want extraordinary treatments unless your proxy sees that you will benefit from it. Here is a Catholic Living Will. Check it out and create your own.