The son's estate will be responsible for the paying of his debts. If there are no assets in the estate, then the creditors will not be paid. That is not to say that they will not try to coerce Mom into paying, but unless she was a co-signor on his debts, she has no obligation to pay them. The life insurance proceeds, naming her as beneficiary, are not part of his estate. Life insurance proceeds are only part of the estate if a beneficiary is not designated.