Living trust, POA vs. guardianship. Any advice?

I had power of attorney for my dad but only had success getting it exercised at one of his banks. The other banks said they needed additional forms filled out by him because the POA was taken out clear back in 2009. There was no way he was going to fill out the forms because he never even knew I had exercised POA at the one bank so I gave up. I was told by APS and others to go the guardianship route. I was awarded guardianship and conservatorship the end of August but didn't have any official paperwork until the end of September and we're still not done with restricted accounts. My dad fought the whole process and is furious that some of the control has been taken away from him. We have allowed him to keep a checking account and he pays all of his monthly household bills. I pay for the caregiver from the conservatorship account. We have issues with some of his other accounts - banks have been tough to deal with. Dad continues to control all incoming money because to take that from him would cause another meltdown. I'm so burned out already. Dad is stubborn, refuses to wear a medical alert pendant and I feel like I'm under the microscope by everyone since I am now responsible for his safety. I don't wish this on anyone. If I thought I could give this to an outsider I would but my siblings would never forgive me. A professional guardian would suck him dry.........................

My sister (who is PoA) spoke with an attorney in IL who recommended guardianship, even though she has PoA (financial, medical, and personal). We have formal doctor's letters indicating my father is incompetent / non-decisional, and my sister has access to his accounts, medical records, etc.

I don't know why the lawyer is recommending this --it seems like it would involve lots of money, hassle, and risks. Very confused right now ...

Why do you want to petition to become your Father's guardian if your Sister is his POA?  Are you asking if you ALSO need to petition for guardianship even though there is a Trust with a POA already in place?  It needs to be either one or the other, but not BOTH.  Is your Father living at home or in nursing home?  We need more information about your situation to offer appropriate suggestions.