Durable Power of Attorney – It's much better (and less expensive) to have one in place BEFORE you need it, especially in the case of illness or dementia. Check out the links below to learn more.

https://dailycaring.com/dementia-and-power-of-attorney-what-to-do-if-someone-cant-or-wont-sign-a-poa/

Durable Power of Attorney Forms by State
https://powerofattorney.com/

Medical Power of Attorney – It’s not all or nothing, but be sure to choose someone who knows and will respect your choices.
https://www.lawhelp.org/dc/resource/frequently-asked-questions-about-durable-powe
http://www.wvlegalservices.org/medpoa.pdf

Medical (Health Care) Power of Attorney Forms by State
https://powerofattorney.com/medical-power-attorney/