Some years ago I purchased a new home with brick veneer that leaked water on to our living room floor everytime it rained hard (house was on a slab foundation). The builder wanted to treat the bricks with waterproofing as a solution. I insisted that if the wall had been constructed properly it would not be leaking through as it was. In the end the builder took the brick down and found the problem to be the fact that so much mortar had been slopped down into the lower portion of the wall in this area that there wasn’t any space between the brick and the frame wall which made the weep holes ineffective and allowed water to migrate through the wall.
Perhaps something like this is going on with the house you are looking at.