Thank you for the additional information. It is helpful.
You state he was afraid of everything and everybody. I'm hoping he has gotten better and is not as afraid of things and people. I think that his anxiety then is still a part of his personality and he is displaying a bit of separation anxiety. As a result he doesn't want to leave you to go out on his own for fear he might be left especially if he was left at boot camp.
Almost every dog loves to follow their owner everywhere they go around the house. I have 4 adult rotties, a chihuahua and 2 4 month old rottie pups and when inside with me, all of them have to follow me everywhere. It is almost impossible to walk unless I order them to lay down and stay. So part of the solution is more obedience training but not by someone else. You need to do the training so he listens to you the first time every time then you can have him sit or lay down and stay until released. Be sure to train for the release command.
The following site is helpful in helping owners train their dog. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
This also helps him gain self confidence as he learns the commands and knows what is expected of him when he hears those words. Be sure to use high value treats for training like hot dog slivers and chicken slivers. It is good to get this training done now since he is fast approaching the age when most male dogs test their owner's ability to lead or be the boss. Often dogs will stop listening during this time and in some cases even growl at an owner to indicate their displeasure if asked to do something they don't want to. With his being insecure already, it may take him a bit longer so training now should help establish you as an able leader/boss and help him gain self confidence.
You might also want to get him a dap collar. They are great for anxieties and separation anxiety as well. They use pheromones to calm a dog's anxieties. You can purchase them online, pet stores and the vet's office as well.
I'd recommend going out with him but have a chair and book or other activity for you to do right outside the door. That way you are outside but not walking around with him. Sit down and let him take his time eliminating even if it takes him 20 minutes or an hour to leave your side and eliminate. Once he eliminates, give him a special treat (hot dog sliver) and then go in. He'll learn that you are not going back in and go eliminate sooner each time you go out. Eventually you will move the chair just inside the door and wait. He will learn that you will let him in once he is done. The important thing is always to be right there so he can see you and you can let him in when he is done. It isn't an overnight cure but has been proven to be effective at solving this problem. Usually it is small dogs with this issue so I would expect training to go quicker with a large dog.
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