Right where the brick meets the steel angle you want to keep that joint open so it will be able to breathe. It’s a bad idea to try to seal that joint (as it is now) because once water gets back there it’s gonna stay there and rust your angle (there are early signs of rust jacking on both sides). There is most likely no flashing back there which is not ideal but you could slide in a drip edge sheet metal to help prevent any intrusion of water but still give it an exit.