Originally Posted by *blackrose
That's how Blackie was. He got to the point where I could have him out in public/etc. on leash and he would ignore other dogs, but if another dog growled or acted aggressive in any way he would become aggressive. In 4H dog obedience he let a little Golden puppy climb over him after it broke its down stay (and before the owner could grab it), but when a cattle dog snarked two dogs ahead of me during a heeling exercise he was ready to kill it.
I've always had DA dogs in one regard or another, until now. It is definitely a management adjustment, but it isn't the end of the world.
Would you be able to get him used to wearing a basket muzzle? Then maybe if/when your mom becomes his sole caretaker, you can worry less about her having to micromanage him if he's wearing the muzzle just as a precaution.
Simi is trained to wear a muzzle, just because she can be a rude bitch sometimes. She loves it. She knows it means something fun is about to happen, and she will run and play with it on like normal, so this might be an option for you.
Also, and since I don't know much about the situation this might be crazy, have you had him to see a vet about this sudden change in attitude thing?