Part of making an estate plan may include making future medical decisions. One way to do this is with a living will. It allows you to make decisions in advance about things like using a feeding tube, being kept on life support, being resuscitated and other matters of this nature. If a medical emergency happens, the living will helps to guide your family members and your medical team.
But could this lead to a dispute? What if your family does not agree with what is written in the living will? For instance, perhaps it says that you do not want to be kept on life support, but family members want to put you on it anyway. Are they allowed to ignore your living will and do whatever they wish, making their own medical decisions instead of abiding by the documentation you have provided?
They need a reason to challenge the will
As a general rule, no, your family is not allowed to ignore your living will or make their own decisions. If you wrote that you do not want to be kept on life support, your medical team will follow those instructions.
That said, similar to contesting a will overall, family members may find a reason to challenge the will. For instance, maybe you drafted your living will after you had already been diagnosed with a serious illness. They may claim that you lacked the mental capacity to make those decisions. They could also challenge it on the grounds of undue influence if they believe that someone else manipulated you or influenced your decision-making.
So, in rare cases where there is a reason to question the documentation, they may have options, but they cannot simply set the living will aside because they do not agree with it. It is important for all involved in a situation like this to understand their legal options.