My father recently found out that his wife had been writing bad checks to several different banks. Is there anyway I can legally place myself beside him but not take away his rights?

taken out credit cards and placed and opened ended deed of trust on his house which in turn gave her access to a substantial amount of money without his knowledge. She has kept the mail from him. We have also found forged documents and he advised to me that they made him sign a blank lined piece of paper. Which I later found was an admittance to writing bad checks, when of course he is illiterate. My father can make decisions on his own if someone reads the papers to him. Is there anyway I can legally place myself beside him but not take away his rights.