Riley is a nervous wreck

Haunted by Boscoe? Riley is growing more nervous by the day.

Crazy dog. He's always been skittish, but this is ridiculous.

After Boscoe died, he spent a lot of time hiding under the dining room table and lying in his bed, alert, head up, listening.  And then he seemed to relax.

But lately he's regressed. He's nervous all the time. Any sound--any sound at all--seems to alarm him. On Saturday, Doug made a phone call. And just hearing the sound of Doug's voice sent Riley flying up the stairs and hiding behind the chair I was sitting in.

If one of us puts away the dishes from the dishwasher and they happen to clatter, as plates will do, he runs and hides.  A loud cough, a bump, set your glass down too forcefully, drop a book--he's outta here.

I feel so bad for him--he just seems not to be embracing this whole "I am my own dog, the lord of my house, dominant to all" thing. We do our best to keep him calm. Don't hover. Speak quietly and in that artificial squeaky voice that dogs love. Stroke him gently.  Make him sit for his food and his treats, to let him know that he can rely on us, that we are actually in charge.

It doesn't seem to help much, if at all.  On walks he startles easily, looks behind him, stops cold and seems uncertain about going on.  In the past we have tried Rescue Remedy (to no avail), a Thundershirt (with little result), a Gentle Leader Head Harness Which Presses on That Calming Spot on His Head (he hated it and tried to paw it off).

So what next? What do we do? Or just resign ourselves to an increasingly neurotic dog?

And what does this mean about eventually getting him a puppy? Would that be good for him, or send him into a complete nervous breakdown?