My parents are the same way.
The compulsion for more stuff is an epidemic for the baby boomer generation. Theirs was the first generation to be showered with plentiful manufactured toys as young children. As teens, their culture taught them to value cars and TVsp. Their adult experience has been a story of steady GDP growth, rising wages, falling taxes / rising national debt, and conspicuous consumption. Unlike those who lived through the depression, most (white) boomers have never had to deal with deprivation or hunger. However, they were told by their Great Depression generation parents that spending is how one obtains happiness.
Now their income producing years have ended. Options for digging out of consumer debt have narrowed. Many are stuck with expectations for housing, cars, and dining that don't match their SS incomes. Most saved nothing for this phase of their lives - because it would have cost them happiness, of course.
As others have noted, your options (and my options) are pretty sparse. Getting young people to change is hard enough, but the over-65 crowd is rather set in their ways.
I've lost hope that my parents will ever own a dollar they don't immediately spend. I'm torn though, about what I will do if they become homeless or need medical care that isn't covered. Will I give up my savings and dreams of FIRE? Will they move in (shudders)?
My plan is:
-Offer many hours of help with things like managing credit card debt, taxes, eliminating subscriptions, help with tasks they would otherwise hire out like home repairs. That is, provide nonfinancial help with hair-on-fire situations like late fees, overdue taxes, etc.
-Recommend selling unneeded stuff, like the boat that hasn't floated in 8 years and woodland real estate they've never visited, but don't be annoying about it.
-No loans or gifts.
-No moving in. They have income (SS and pension).
-Periodically ask if they are still enrolled in Medicare. Fix it if not.
-Look into options and programs like Section 8 housing, food stamps, or senior care, if needed.
Other than that, their choosing to live a stressful hand-to-mouth spendthrift existence and refusing advice is outside my realm of control.
For your parents, the homelessness situation with no awareness of how to cope is a big problem, because they are about to lose any home equity plus their personal property that could have been sold on an estate sale for a few grand or might have to be replaced. They'll probably pay a hotel night-to-night after the sheriff evicts them, and maybe rent a storage unit or three. They'll probably lose track of their bills and paper in the chaos, leading to late fees. They'll probably fail to cancel utilities and telecom after they are evicted. A lot of their NW is about to evaporate because they can't emotionally cope with the loss of merchandise.
Yet, you can bet they will buy more unnecessary crap even in their hotel room. How else could they restore their happiness?