Looking for someone better than me at training dogs

[The Great Sage]

I have two dogs - a spaniel who is older and basically a genius, and a mutt rescued from some reserve somewhere

My problem is that this puppy I think is traumatized. You can't move towards him quickly or he'll get skittish, basically inhales his food (I've been hand-feeding him since we got him which stopped the food aggression with the other dog). And he's pretty much an idiot. I've been working on 'sit' and 'lay down' but he's not quite grasping the finer points of the lessons. I've been training the dogs 'together' because I figured that the older dog that has all this stuff down already could sort of lead by example. Now I'm starting to doubt. Am I making a mistake here?

Anyone had to train a supremely stupid puppy before? One that probably had a human kick the tar out of him at some point? I'm sort of at my wits end here because if I can't train him to sit, I can't train him to stay which means I can't train him to chill the fuck out which means he'll never stop attacking anything that gets near the house - people, dogs, cars, shadows, invisible presences, ect..

 

[DemonKitten]

I think a good start would be just teaching him praise. It sounds like he doesn't know what a reward is or what stands for good. You have to retrain that into the pup. I was a dog trainer for a few years and I worked on dogs with aggression and other behavioral problems and it was all about showing them positivity. I think your pup just doesn't know positivity and you might just have to have him do something randomly and shock him with love and treats until he gets it. After that, I think he can do it!