Rene, This sounds very similar to when we brought Lance home a bit over a year ago. It was several days before my husband could even touch him. Every little movement set him off. The key for us was consistency and calmness. If Roo is interested in food, your husband might try hand feeding him. Don’t ask him to do anything for the food – just deliver to him one handful at a time. But it really just took time. For several months, we had to be extremely careful about having anything in our hands / arms when he was around. He was scared of everything (which I think was a learned survival mechanism from being on the streets). I discovered that if I set the object on the floor, he was more likely to come check it out. I did have to use the technique that Robert used with Goofy and the balloons for some things such as boxes. Over time, though, I taught him a “Check it out” cue. He learned that if I told him this, the object was safe for him to come sniff. That took a long time, though. There are still times when I have to put something on the floor first and then tell him to check it out, although the need for that has diminished rapidly.
For confidence, work on some simple obedience using all positive reinforcement with luring and shaping. Lots and lots of reward and encouragement, but I learned to keep that calm and relatively low key. If I went into my upbeat trainer mode, Lance would look at me like I lost my mind. He seemed to gain confidence when he was given a command and knew what was expected of him. This was true even for situations when I would normally keep the dog moving to reduce stress, such as when we would come across someone else on the hiking trail. For Lance, taking him a little off the trail and having him sit worked much better than keeping him moving. Movement seemed to trigger his flight instinct and then his brain was gone. Sitting allowed him to watch and actually have to think things through. So, listen to all the advice, but then watch your dog to see what works best for him. They are all individuals.
Look for and celebrate every tiny success. The times when he checks in with you without you asking him to. The times he approaches your husband to sniff him. The time something startles him and then he looks at you for guidance. As you get to know each other better, you will learn what “success” is for him. Be patient because it takes a lot of time. After 18 months, Lance has a strong trust in us and has come further than I ever expected him to, but he still surprises me at times, both with unexpected startle reactions and with sudden leaps in improvement. Within the last month, he has actually started engaging in play with us at times! He has never shown any interest or understanding of play until now. So be prepared for this journey to take a long time but it can be so worth it!
If you have any specific questions, please post them and we’ll try to address them. You are still very early in the process of developing a relationship, so don’t get discouraged. I have usually heard it said that it takes 3 months to a year for a rescue dog to really start settling in and there can be huge behavioral swings in that time. Good luck to you, and I’ll look forward to hearing about Roo’s development over the coming months!