My grandparents have selected me as their durable health and financial power of attorney. Now after years, my family wants to help and chime into helping with their finances and medication. It is a big concern that everyone wants to have a say in everything. This only happened after my grandfather become very ill at the start of the new year. He has improved and doing well.
Make it clear in the nicest possible way that grandparents are of sound mind and get to make their own choices about how they spend their money and how to manage their health care. I'm going to assume that you are currently backup (that you use your POA to do their bidding and not to make decisions for them; in case they become incapacitated that is THEIR CHOICE. "Regretfully, as their POA, I am duty bound not to disclose their financial arrangements".
Eli, that might solve the squabbling right then and there. But I would be especially cautious about allowing others to help with finances; that's one aspect that should be handled by you, unless you have a specific written agreement with one of the relatives.
Medication is another issue: do they want to buy the meds or administer them?
Barb also provides excellent advice on privacy, and maintaining authority of control assigned to you.
So, when Grands are no longer able to make decisions for themselves, the POA gives you the authority to make decisions based on their wishes. You need to be aware of this. I think Grandpa's illness made the rest of the family aware he could pass anytime. The vultures may have landed. Anytime children are not involved, they seem to swoop in when a parent may be dying. So you need to be strong for Grands and stand you ground. They made u POA for a reason. You have the control.
I like Barb's idea. Give everyone a detailed list of what tasks you would welcome help with and when they need to be done. There isn't anything you can do about people voicing opinions on the medical decisions. If your grandparents agree, maybe they could be updated on medical conditions and even treatments. But that would only be if it were okay with your grandparents. If it isn't, you will have to keep saying "You'll have to discuss that with grandpa."
You will get "second guessed". Just brace for it. People are dealing with their own anxieties when they criticize. Try not to get upset. Thank them for their input and then go ahead and. make the decisions you are going to make.
And my other advice is to not try to control everything. If they will take over a task, don't get too excited if it isn't done the way you would do it. Just let it get done. Pick your battles. Some things you will have to hold a hard line on but let as much as you can slide.
Having help (Even annoying help) is better than being alone with the huge job of caregiving. Good luck.