Does that mean Nancy is running the Brick account? And why are we bothered?

No, Nancy doesn’t run this account. She commented on .a picture not long ago about how happy she is to see pictures of him on her feed again and how she misses him. But now that Monique isn’t in Vancouver and so doesn’t have access to Brick, “Brick” posts pictures taken by Nancy (he just did that again with the Trump doll) months ago and reposts them as if they’re recent. I don’t think it’s a coincidence we only get new pictures of Brick whenever Monique is in Vancouver. 
And it’s annoying, because it’s confusing, because obviously she can’t do her job correctly and mistake Brick for other dogs and this account is all over the place, even posting paparazzi pictures from the day David’s best friend passed.