From the Residential Customer Agreement (RCA):colebert said:
D. If your Services are canceled or disconnected for any reason, you are still responsible for the payment of all outstanding balances accrued, including without limitation any applicable Fees.
Unable to find the word "death" anywhere in the RCA. Usually any assets that a deceased has remaining, stand "good" for any obligations remaining after death.
I'm not a lawyer, but it appears his estate will be liable.
It's tough to have a friend pass away. May he rest in peace.