At wits end with Apollo
I agree with the other posts, hormonal imbalances can cause big changes in behavior and, it sounds like his moods are all over the place. Also, if he is scared of things he could act out aggressively due to lack of confidence. There is also the fact that not all dogs are happy in homes with other dogs. There's a lot you could be dealing with.
Either way it seems like you've added more chaos to the situation before nipping these behavioral issues in the bud. Also if you don't have time to stimulate him, he could also act out. My German shepherds get to be real pains if we don't keep them stimulated with play, practicing commands and, tons of exercise. Just saying, it could be a lot, hook up with your vet on this then go for a trainer.
This kind of thing was suggested back in 10/11, was anything done then, other than adding two more dogs?
It's not the dog's fault, it sounds like a clear and distinct lack of leadership in the home. Plenty of owners seem to believe dogs should just be
good dogs, without having to invest time in the situation to improve it.
However, those kind of dogs are the exception, not the rule. With a dog like yours, he's going to take a lot of work to engage him and keep him engaged.
Another thing that seems to repeat itself in your threads, and that's "He KNOWS when he's bad/done wrong, etc.".
That's really not true. Dogs only know we're upset, they really do not know or understand why.
If you're reacting in anger towards this dog because of what he's doing, he just knows your freaking out, or angry or whatever, but they don't have the reasoning capability to understand why you are.
They will slink around and people are satisfied, based on that, that the dog "knows" it's done something bad.
I'd recommend reading some books such as "The Other End of the Leash" and even Temple Grandin's books such as "Animals in Translation", to get an understanding of how dog's "think".
And get a trainer on board, have this trainer come observe the household, the dogs interacting and how you interact with the dogs.