Debts and death, question?

My dad just died of a heart attack a week ago, leaving my mom and me to fend for ourselves. We know we must continue to pay on the mortgage, but are we still liable for his credit card (only in his name, mom had not authorization on it), the cell phone plan (rogers family plan, again in his name with only my mom and I on our #'s) , and his "contract" with direct energy (more like crooks)? any money we do get from is insurance and disability plan will be our livelihood for the next year, he didn't have any investments or any other methods of income. We had just got a truck too, but it's paid off thanks to life insurance he got when buying it. So what must we pay, and what must the creditors absolve?