Fixing wall with constant moisture over the years

I live in Mexico where most of the houses are made by brick and cement. Over the years we have had moisture in the walls as shown in the images below.

As you can see, it looks like if the wall is falling apart. Even in some parts of the walls with this problem, we don't even have pipelines where it could be a potential water leaking. We have checked and we don't have any of those.

We have hired several masons to fix it and we have bought a lot of different chemicals and very powerful acids that eat the cement of the wall in order to kill the moisture but we have not succeeded, yet.

My dad told me that long time ago people used to put big chunks of charcoal in vases that sucked all the moisture from the wall but it seems that is a very old way to do it and the house would not look pretty with vases all over the house.

Is there a way or method you know in how to fix this for a long period of time?