How to fill gap between brick and drywall?
If you want to fill a large gap with caulk, the first thing you do is fill the gap with a caulk "backer rod" that's made of foam. They come in various diameters are are typically found near the weather stripping in a home improvement store. You shove the backer in with a putty knife (not too deep, just enough to be below the surface), and then cover with caulk.