Surprisingly, some couples with considerable assets do not have their affairs in order meaning they do not have good estate plans in place. It is important to sit down with family members, sons or daughters and have the What If discussion. What if Mom dies. What if Dad dies. Things can change very suddenly if someone falls ill especially if that someone is the spouse that handles all the couple's finances and the other spouse is clueless.
Ideally, most if not all payments should be on automatic debit from a checking account so that at least necessary payments will continue without late penalties. If one spouse dies, the other will get the higher of the two Social Security payments; but it still means a sudden loss of income. The time to deal with housing issues is while both spouses are healthy. If living in a multi story home, maybe its time to downsize to a one story house that would be suitable for the surviving spouse.
Fortunately, we moved my parents into a 55 or older gated community long before my Dad passed away. Since my Mother handled their financial affairs, she experienced no real disruption in her life when my father died. Had my Mother died first, my father would have needed assistance, but at least the housing situation would have been fine.
Once someone turns 70 every year is like a dog year meaning the equivalent of 7 years. Health circumstances can change suddenly, which requires a quick reaction from family members to deal with the medical issues at hand. Most important, every couple of any means should have a good estate plan in place to deal with the What If's. And, families need to be involved to best understand what could happen when the first parent suddenly passes away.