My dog is suddenly afraid of neighbor?

On Nov 7th we had to put our 13 year old dog Sammy down cause she started war with the neighbors dog. Well the neighbors dog Callie had been living near us for a year and everything was fine until October. We came out of neighbors house on afternoon and were standing on hindmost porch when for no reason sam attacked callie. Out other dog Buddy didn't get involved in any of the fight, just kept his distance. Well the fighting got worse to the point where on earth we had to keep sam and callie separated because every time they got to hand each other sam would go after callie. You could see something change contained by her face she looked crazed. The weekend before sam was put down they have gotten into it again and me and the neighbor had to pull them apart, I know stupid to catch involves in a dog fight put sam had callie by the throat and we be afraid she would rip her throat out. So i had to put my hand in her mouth to pry her jowl open and then the neighbor had to do the sam near callie to get her off sam and she got her hand torn up. She came over to our house so we could clean her up and dress the wounds, she was markedly very upset and crying and buddy was in the mode while trying to get in the house and they yelled at him to gain out of the way. Well now buddy acts afraid of her? He have no problem letting her in the house and the whole time shes over he's fine but if she reach out to pet him he runs away either outside or to one of us to acting close to protect me. I don't get it? Any advice?
The dog somehow associates the neighbor with Callie attacking. Have the neighbor give your dog treats when he comes over.

As for it mortal "stupid" to break up a dog fight, no, it's not stupid. It saves one dog from mortal killed. It's always best to break them up...in most cases besides.

Edit: Don't listen to the jerk above me. We had to put a dog to sleep for the same drive. The dog started having neurological problems and became mean. She attacked my other dog a few times, and afterwards bit my mom. The vet diagnosed that problem, so we decided to have her euthanized.
I would NEVER put my dog down because of a neighbor's dog.

You just save them apart for crying out loud.
Answers:    How sad that Sam have to pay for your inability to manage your dogs.

ADD: You didn't say Sam have any health problems, just problems with Callie which is the neighbors dog. I am never going to euthanize my dog because it can't attain along with the neighbors dog. The neighbor could just keep her dog at her house and I preserve mine at my house. If Sam was suffering from a health issue you did not mention it.
If I bought a pure breed puppy from a breeder,individual to find out he's a mix breed, what legitimate undertaking can I embezzle?   Why is my dog pooping blood?   I cogitate my dog have an eye infection. What can take place whether it go untreated for too long?   Im am confused, puppy question?