if you have power of attorney for a friend that died are you financial responsible for funeral expenses?

A power of attorney does not survive the death of the party who granted it.  At any rate, all it does is empower one party to act for another.  It does not impose any personal financial responsibility on the person who has it.  Thus, for example, you may take out a bank loan for your friend if he has authorized you to do so with a power of attorney, but you're not responsible for paying back his loan if he doesn't.