As I purchased the house in winter there was little danger of the foundation completely caving in for a couple of months. However, it was imperative the work be done prior to the spring rains.
As the wall was bowed in about a foot, they installed four steel beams, two in and two outside, with threaded pipes through them and the block. Then, using nuts, they slowly pulled the blocks straight.
The original estimate was $11K; my guys did it for $4K (including re mortaring the blocks and replacing the small windows).
There were a couple of other places that required block work as well –
The cats weren’t happy!