Again, the law treats other relatives and relations different from the spouse in the event of death (or divorce). Prior to my divorce, my ex opened up three credit card accounts, without my knowledge and without even putting me on the application. Yet, during the divorce I was held liable for 1/2 of the debts because we are in a community property state, where the law treats a married couple as one person.
While Mike, as son, (nor any other family members are) is NOT responsible for any of his mother's debts. Depending on the state, had it been his wife he could have possibly still been on the hook. (If it is a community property state).
Which is generally why in the event of the death of a spouse, the estate flows directly to the surviving spouse without having to go through probate.
Last piece(s) of advice.
1) Prepare wills or living trusts, so that your final wishes are in writing as to the disposal of your assets.
2) Pre-pay your funeral. I know people will argue against it. But I find great comfort in know that some shyster funeral director won't be trying "up-sell" my son on caskets and all the other crap that funeral industry pushes on the grieving ("He would have wanted the gold-plate burial vault..."
) surviving family members. I saw it when my step-father-in-passed. My mother-in-law bought everything the funeral director recommended. Most of which was needless and a waste of money that she could have used (although knowing her spending habits, throwing it in a hole in the ground did about as much good.)
And I saw the opposite when my father passed, he had everything pre-paid, so there was very little for us to other than to tell the funeral home to pull his file and do what was in there. And we probably saved several thousand dollars over what it actually cost.