How do I help my great uncle who is now in a nursing home?

My elderley great uncle is now in a nursing facility. He has nobody but my brother and I an we need to be sure all his medical needs are taken care of while he is there. He doesn't have any legal paperwork and they keep telling me since he is ward of the state, there should be some sort of papers signed so that we can make a decision if something should happen. I have no idea where to go with this. He is in his late 70's, deaf and now partially disabled. We don't want to be responsible for monies, but want to be sure he is getting the proper treatment. Can someone shed some light on this for us. Thank you.