Some bad financial decisions have left my dad deeply in debt. I'm his Power of Attorney, but he gets angry when I try to guide him financially. The POA seems useless. How can I help him?

You aren't missing something. Even though you have POA (and you should), he may resent you trying to tell him what to do. You are his "kid!" He may feel guilty about what happened in the past or that he is blamed.

A third party often has better luck as they are not emotionally attached with all the baggage that goes along with it. You want to see if a friend of his could help out, or get a financial person to lend a hand. It's quite possible he would cooperate better, then. Good luck,
Carol

Get a lawyer; you may need a guardianship, and maybe there is some possibility of suing the phony female friend who took advantage of him. Take a look at http://www.hg.org/article.asp?id=18705, http://www.seniorsummit.ca.gov/materials/betty_malks.pdf, and/or Google "successful lawsuit elderly financial abuse." This is unfortunately not uncommon and results in destitution and even impacts health and lifespan for the victims.