The studs in the exterior wall were just cut out where the windows were placed. Obviously there was no understanding what had to be done.
Carpenters are trained to know that whenever a structural wall is modified with an opening, then the opening has specific buiding code requirements to redistribute the load. Typically a new beam is installed over the opening to transfer the load to the sides. The sides are also strengthened to take on the additional load that they now will have to carry.