2 years ago we rescued a 4 yo Golden Retriever girl from a puppy farm (mill). She was terrified of my husband from the get go. However, I read a great paper on-line on how to gain these pups' trust.
It begins by making sure only good things come from us. So we should carry treats with us at all times and every time we pass the pup at any time of the day we should drop a treat, along with soft words, and keep walking. We fed her near where she huddled until she was comfortable enough to come into the kitchen with our other dog, setting her bowl closer to the feeding station each day. Took about a week to get her to do this.
It took about 3 days for her to begin to expect something when we passed and to trust that we were good people. I was able to sit near her ..... about 3 feet away and talk gently to her (with some treats); but didn't physically touch her until she was relaxed enough to start little explorations of our house, and to join us and our other dog as a group, i.e. sitting together at night after dinner, and sleeping in her bed near us. Slowly over the next 2-3 months she allowed us to touch her at arms length, albeit warily, and within another few weeks she started to sleep without laying on her tummy (quick get-away position) and began to stretch out. At all times her bed was located with at least 2 escape routes.
After about 6 months she allowed my husband to give her a tummy rub one evening .... we were over the moon. Her tail had started to sway as she moved around our property and now, she wags her tail happily when she hears our voices, she accepts bear hug cuddles from us both, comes to us both for her multiple daily pat sessions, and rolls over for her tummy rubs at any random occasion. My husband and I each feed our pups, he does breakfast and I do supper, always.
She still sometimes likes her privacy and we respect that. We have been able to train her to do basic commands.
The whole thrust of my post is TIME, PATIENCE, and GENTLENESS to gain her trust. I know how hard it is when all you husband wants to do is love your pup, but he cannot rush it. Progress must be on her terms - hubby just must stay consistent.
Good luck ..... it WILL happen.