Would POA help me?

I care for my elderly parents 75/77. I have two brothers, get no help from them. They want to make all decisions. One lives in same town, other one does not. They don't help financially, emotionally or physically. My parents live with me, both have beginning stages of dementia. I have a state funded service that helps with medicine and a few hours a week personal aide assistance. The last disagreement was I wanted to hire my own person to come into my home and assist them when I am at work. The state company has a rate they pay and I wanted to pay out of our pockets $4.00 more an hour. This is a person I know and trust in my home when I am away and I know she would take good care of my parents. She also does patient care as a living.They wanted to just have the state agency send a stranger and get paid for only what the state offers. The only financial assistance I have asked for in the 4 years I have been caring for them. They are both on social security only, from low income jobs. I have only asked them to pay utilities. No rent, I cover everything else. The pay their own car insurance and life insurance policy premiums and any toiletries and clothing they need. The story could become a book but I want to know would it be best I get POA. I am still able to discuss things with my parents and they understand, but I need to get things in order now before they can't make any decisions. What other documents should I get and is it necessary to get a lawyer because my funds are low too.