"Also is there a concern of structural problems?"

No, they just did nit build out the wall above to the same thickness as the concrete stub wall. Your welcome to build it out if you wish.

I'd furr out the wall all around the room to the height of the bottom of the window stool and integrate the windows stool as a cap for it.

^^ That won't work because of the windows. Red circle, look up. See window?

On second thought, you could fir out just the section of wall that is under the window, wrap around the column, top with Corian & have a deeper sill/ live plant shelf.

Except the photo looks like the windows are different sizes? Not the same distance from the floor?

@ci_lantro,

If you'll re-read my post, it describes exactly that. There's no reason the height at the cap can't be varied at various sections of the wall.

Yes, you did, Chas. My mistake.

Thanks everyone, I've decided to build a reading nook just below that window to cover up the foundation. Also going to be furring the wall in other areas where foundation is bulging.

Thanks!