My grandparents have a "property they can now sell". They never will. They've been investing in it and adding to it for so long that it has become useless to any potential buyer, and parts of it are now so old they really really need repairs.
They cannot afford to sell because the investment to make it sellable for a good price is too high. Nobody would want to buy because the investment to turn it into a useable large house, is too high.
So instead they turned a tiny part of the house into an apartment for themselves because the costs of living in the whole thing are too high. They turn on the heating in the rest of the house just enough during winter to keep the pipes from freezing.
None of the kids want to inherit the property. None of the grandkids want it either.
The location isn't that great either because the economic activity the location was great for (wine) is now in tatters and the government is paying people to please for the love of god stop making wine and cut down their vineyards.
My mum has a nice flat in a downtown area. She recently had to go into debt to afford to fix it up. She could potentially sell, but then she'd have nowhere to live. She's too young to buy a rural house (same price) because she still goes to work. She's too entrenched to deal with finding a new apartment somewhere else. And she'd have to pay more for a new apartment than she'd get for her current flat. At 50-ish, she also doesn't really want to go into another 10+ year mortgage.
So ... no, I don't see the value in owning.
Basically: Having all your wealth tied up in an illiquid asset is twoplus not good.
Regarding your mum - I assume there are rent controls in her area - in mine (Western US) there aren't necessarily those. If she rented she'd have been priced out of her flat years ago as the landlord ups the rent to market rates or "renovate".
Its still assets at the end of the day, no? Just because they don't sell it or they put a lot of money into it doesn't mean they can't. A renter doesn't have that option. I'm not making claims about its efficiency as an investment vehicle, I'm simply pointing out that in the example that I replied to you they'll end up with an asset worth more than the $40,000 they saved by not buying.