Need Dog Training Advice

Hello everyone,

My name is Joycelyn and I have a 1 year 9 month old white german shepard named Sugar Kane. He doesn't really respond to the the Sugar part of his name so we just call him Kane for short. We have had Kane for 3 months. We adopted Kane from the OC Animal Shelter, we were told he was returned 4 times because he had too energy, the previous adopters did not have time for him and he has seperation anxiety. Kane has settled in very nicely, he gets along with our cat, and after at least 20 minutes of exercise which is usually a dog park visit he just lays around and is calm. Kane is our new best friend. Kane is currently going through training at our local PetSmart, we are in our 5 week of beginner level training. I purchased the bundle package of beginner, intermediate, and advanced classes so I hope he can be very well trained in the future. Kane is a very smart and wonderful dog, but he does have a few behavioral issues I would like some advice on how to correct soon or in the near future.

1. Kane will bark and growl at my dad. We have a theory that Kane was once abused (we think by a bad breeder). We theorized this because he would bark at adults that had their hands in their pockets and if you move suddenly he flinches. He also struggles to understand dog play fighting, he is always playing referee as though he is trying to break up 2 dogs playing so that they all don't get punished. Our thought process is that a possible bad dog breeder would not let the puppies play so that their merchandise does not get damaged. We think the fear of pockets comes from someone in his past having something in their pocket to hit them with to probably get them potty trained sooner so they could be sold. We have since showed him that pockets are good with cheese sticks being pulled out of pockets and given as treats, that was an easy fix. Kane barks and growls mostly at my dad but sometimes at my mom too. I myself am 23, but I am petite so I don't think Kane considers me "a scary adult". My brother is 20 and again Kane does not bark at him. My dad and I were the ones that brought Kane home. Kane spends the most time with me so we have bonded very well. We guessed that since he had already bonded to me he would only be vocal to my dad to tell him he did not want to be returned back to the shelter. We thought the barking and growling at my dad would subside after realizing he was finally home and would not be returned to the animal shelter like he had been through 4 times before, however, it is still an issue. I have asked the PetSmart trainer we are working with and he suggested that my dad try to bond with Kane more, but unfortunately my dad works long hours at a physically demanding job so even just feeding Kane is a lot to ask, let alone a walk. My dad is getting sick of Kane's barks and growling especially since my dad spent $240 of what little money he has to adopt Kane for the family for Christmas after grieving the passing of our last dog. One night my dad got so mad he made Kane spend a couple of hours outside in our backyard when it was pretty cold (we live in California so don't be worried it was just a little chilly). My dad and I think that Kane does not know how to submit because of his possible lack of puppy play when young. I take him to the dog park frequently and when other dogs submit to him he seems to have a puzzled look on his face. I know that for Kane's age it might be hard to teach him how to submit but does anyone have any advice to get Kane to stop barking and growling at my dad?

2. How do I get Kane to stop eating paper tissues, other trash, and socks? I have tried using a PetCorrecter air spray can that sounds like a loud cat hiss to get him to stop and when he changes his focus to something other than the trash can I try to use positive reinforcement and give him a treat for leaving the trash alone. However, when he is left home alone I frequently come home to my room with trash sprawled across the floor. I also keep a small trash bag in my car and when I put Kane in the car he immediately swallows napkins before I have even opened my door. Kane also very quickly steals socks out of laundry hampers and eats those before we can even get near him. He has thrown up 4 socks in the past 3 months we have had him. Should I try to use a bitter spray made to prevent dogs from chewing on things? Any other advice or tips would be greatly appreciated.

3. How do I get Kane to stop barking at one dog? I have noticed that when I take Kane to the dog park and there is another dog there that is more shy, smaller, less active than him, Kane incessantly barks at that one dog. Kane is very active and LOVES to run, and I understand that as a German Shepard he may be trying to herd dogs. However, sometimes when one dog is staying close to their owner and is a smaller dog, Kane becomes super obsessed and will not leave that dog alone. We have learned the command leave it through PetSmart training but it does not work in this senario. I feel so bad when this happens because the dog Kane is sort of picking on is probably already shy and does not want to run or play with him and is more focused on feeling safe, smelling things, and playing fetch. I have tried multiple commands: come, leave it, touch, settle, but nothing works. Kane is pretty good at listening to commands but when he is distracted it is a hit or a miss. I also try to lure him away with his toy balls and squeaky toys, but that does not work either. I eventually am able to grab Kane's harness and pull him away from the other dog but no matter how far I take him away he eventually goes back to continue barking at the one dog. In the end, if Kane continues this behavior, which he usually does, I end up hooking up his leash and we leave the dog park because I do not want Kane thinking that behavior is acceptable and I want him to know that if he does not listen to commands we end up going home. I want to make it clear that I do not think at all that Kane is being aggressive when he becomes obsessed with one dog at the dog park. Kane never bites the dog not even playfully and frequently bows down, putting his chest to the ground with his rear end up in a playful manner. Does anyone have any ideas WHY Kane becomes obsessed with one dog at the dog park? I want to fix this problem as soon as possible as I feel terrible for whichever dog Kane constantly barks at and I myself feel embarrassed I can't control this specific behavior so any training suggestions would be great!

Thank you for reading my lengthy post, any and all tips, advice, and training suggestions would be greatly appreciated!