I need to increase the amount of his monthly transfer from his savings account to his checking account in order to pay for his nursing care. We have a joint checking account. My name is not on his savings account.
Are there other siblings in the picture? This has the very good potential of having sibling question your motives and use of dad's money. Just make sure you document, document, document! Keep all receipts, create a spreadsheet showing where dad's money is being spent.
Contact the bank and they will give you a form for him to sign and return. A Guardianship definitely requires a lawyer and evaluation of your father to determine his competency. You will be background checked and have to appear before a judge.