What questions should I ask of a structural engineer about these cracks in my brick walls?
Get a reputable professional structural engineer in there ASAP -- it looks like the wall is severely cracked and would fail at that point when subject to shear loads.

I'm sure that the eyeballs of said engineer will tell a story when he sees a wall that's cracked that badly.

Also,

WHO THE HELL BUILDS WALLS ATOP LOOSE EARTH?