How to train my dog to be less scared of strangers and other dogs?

Hello, sorry to hear about Oscar. There are some things you can try at home to manage his fears. Here are some basic definitions and tips to better orient you, however, successful management of his fears may require patience and time as counterconditioning to the stimulus can sometimes take a long time. Hope this helps and best of luck.

DOES YOUR DOG HAVE FEARS?
Fear in a dog may present in a variety of ways. Recognizing that your dog is indeed fearful is the first step. Some signs that a fearful dog may display include: tucking its tail between its legs, lowering its head, shaking or trembling, lip licking, rolling over to expose the belly, urinating, or becoming immobilized. A scared or frightened dog may also display aggression, including barking or growling, if it feels it cannot escape what is feared. Avoidance behaviors such as running away, hiding or backing up into a corner may also be seen.

WHY IS MY DOG FEARFUL?
Many dogs are fearful of specific stimuli or situations. These fears may stem from a lack of exposure to the stimulus, or may develop due to an adverse experience. Both can result in the dog having a fearful, emotional reaction when confronted with the stimulus. Often dogs respond fearfully to things in their environment that in nature would be potentially dangerous, such as loud noises or strangers. This behavior can be troubling for owners to watch. Often, owners become concerned that they have done something to make their dog fearful and their natural reaction is to try to comfort the dog which may amplify these behaviors.

WHAT CAN YOU DO TO HELP YOUR DOG?
1. Identify specific triggers
This is an important step in moving forward and helping your pet overcome their fear. Knowing what stimuli are a “triggers” is key in creating a treatment plan because it allows you to have more control over the behavior and avoid such stimuli when possible.

2. Avoid the stimulus
Initially it is often best to avoid the things that will trigger a fearful reaction. This may provide an opportunity to work on your relationship with your pet and develop trust without distraction.

3. Define your relationship with your pet
How do you and your family members react to the behavior? Often times the natural reaction to the fearful pet is to comfort them by petting or picking up small dogs. This response may enhance the dog’s reaction to the fearful stimulus because they perceive the comfort as positive reinforcement of their fearful behavior. Rather, a more appropriate reaction is to act as though nothing unusual is going on and try to redirect the dog’s attention to you through a “look” or “sit” command and then treating that behavior. Some dogs are so fearful they may not be food motivated. Perhaps there is something else that your dog considers a “treat”. You may use this in the place of food. In these cases it is essential that all family members are consistent and treat the dog in the same manor.