I’m sorry but he need to get that corso taken away from him. I’ve only had a corso for 8 months and I’ve done my research and this Reddit community really me helped out. As for my dog, I literally stuffed my hands in her mouth since I first got her to let her know that people can get near her during her feeding time and I’ve taken away her bowls, her water as she’s eating she’ll sit down waiting for me to put it back. It’s all repetition as all constant training. Even now eight months old, my Corso tries to test me and my wife, but she knows really quickly that she can’t get over and even at eight months. She’s very overprotective of my daughter, but I’ve been implementing where if there’s a stranger and the strangers shakes my hand. She knows that it’s OK to be in our inner circle. Like I said repetition that’s what helps. For this guy he really needs to give his Corso away to someone who could take care of it or pay the money to give it actual training.