Foundation crack ? crumbled concrete ?

Hi I would like anyone and everyones advice on the following pictures.

The owner of the home has so far received multiple descriptions from various professionals of the following pictures it is a 1960 home :

-Foundation crack needs to be sealed appropriately by a foundation expert
-regular deterioration of foundation
-curing process never fully completed which after so many years resulted in crumbly surface of concrete
-a case of loose parking

Please only good feedback

Where are you located? Need more information about the foundation type?

I can see where a crack in the wall is deteriorating.
That is mostly due to weak concrete at that time and prolonged moisture contact. The crack is possible to have been there since it was poured due to shrinkage and/or settlement.
It should have been excavated when they did that parge coat and repair properly at that time.
Looks like it was originally formed up using boards. Residential concrete foundations back then were lucky to get concrete anywhere close to 2000 psi. and most likely lacking any reinforcement.

Pictures of the interior would help.

A qualified concrete foundation contractor should be recommended to fully asses the condition of the foundation and work with a structural engineer if deemed necessary.

The majority is obviously parge coat.
The severe concrete deterioration at the base of the wall might have any a number of causes, including salt- or chemical- contaminated mix water, maybe freezing soon after placement. As Marcel said, looks like long-term moisture issues contributed significantly (visible efflorescence). Calling it a “crack” is pushing it, the crack has done rotted away!
At any rate, recommend foundation contractor if you know a good one, or a structural engineer.