Recent dementia has set in and cheques have had to be assisted with although she has no memory of who grandchildren are. Brother in law has suggested his wife older sister is made power of attorney although she does not deal with household or financial matters herself so likeihood is that he will be dealing wth matters.
Some people with POA go on a power trip. Others dig in their heels and demand that things be done their way. There can be control issues, a lack of wanting to compromise. The problems are endless.
There should be only one POA and if the other siblings feel left out then the POA can delegate tasks to the other siblings if the POA wishes. As the eldest sibling I was POA for both my mom and dad but I called upon my brother's assistance and we split the duties. I took care of everything medical and he took care of everything business. It worked out very well and my brother was a tremendous help.
I hope you will think very carefully before taking this step and consider only 1 person for POA.