Committed to Helping Our Fearful Rescue — Looking for Guidance

I want to preface this by saying that we are fully committed to keeping our dog and giving him the best life possible, whatever that may look like. We’ve had our new dog, Fergus (a ~2 year old Scottish terrier mix), for about 8 weeks now. When he arrived, we were his third home in a months time due to his extremely shut-down behavior.

We don’t know much about his history before his first home, who adopted him from a shelter where he arrived as a stray. Both previous homes reported the same issues we’re seeing now: he is extremely shut down, shows very little interest in anything, and doesn’t initiate interaction. We were prepared for some challenges, and we hoped that a quiet, consistent environment would help him settle.

As expected, he is having a tough time. Even after 8 weeks, almost everything still scares him. His appetite is okay if the food is placed directly in front of him, but he isn’t willing to interact with us at all. We have given him space to decompress, and our vet confirmed he is physically healthy. The vet did recommend an anti-anxiety medication, which he has been on for about two weeks now.

The reason I’m posting is to ask: is there anything else we can do to help him? He isn’t treat or toy motivated, and he doesn’t enjoy attention, so we’re struggling to create any kind of positive reinforcement. He does love being outside and playing with other dogs, so we’ve considered adopting a second dog, but that feels like a big step given the current situation. We want to let him progress at his own pace, but his quality of life seems low right now because he is so fearful. We are committed to giving him all the time he needs, but I’d love to provide him with any additional support we can.

Additional context:

• He has full access to the house and a doggy door that leads to a fully fenced yard (which he doesn’t use).
• He has a kennel for a safe space and several beds around the home for additional comfort.
• We have tried many types of treats and toys, but nothing interests him.
• He loves going to the dog park and will play with other dogs, but he avoids interacting with humans.

Any advice or insight from people would be greatly appreciated.