Pictures?

We need pictures. Also, is this real brick or brick-look tile? If you hate how it looks how stop and have him remove what he's already done.

Paint it any .color using chalk paint

Someone else on this forum just used it on their backsplash

So chalk paint on a backsplash will last about a month and brick is really one of the worst materials for a backsplash so either ditch it or paint it with a good epoxy paint it will look like white brick