Have them recess the boxes into the brick.

Before the mortar cures you should pull them all out and set them aside.

This allows you to easily drill through the sheathing behind the box to run a cable to power it later.

You can ten put the boxes back into the holes and use polyurethane caulk to anchor them.
The front edge of the box should be flush with the face of the brick.
A little proud is acceptable, but recessed is not.

Thank you Brickeye. My builder has suggested a simple piece of pvc pipe that the bricker bricks around (a hole for the wires) and that the fixtures be mounted into drill holes in the brick.

Any thoughts on that?

"Any thoughts on that?"

Simply not allowed or adequate.

You need a junction box behind the fixture canopy to make connections

piece of pvc pipe that the bricker bricks around

Makes me wonder about your builder.

BTW, the term is mason.