I'm sorry I missed this thread until now, and truly sorry for your loss.
But I look at my dog and It takes all I can muster to hold back the tears. We never knew anything was wrong. He never gave us a sign of trouble. And we take our dogs to the vet multiple times a year. I guess I wish i could just have him understand one thing. That we are sorry and we love him. His sister seems to be very depressed. As if she knows something is wrong but again there is no understanding.
That and diesels sister (been together since babies but had different parents) another pug named harley, is very confused. She goes to areas of the house he used to sleep and she just whimpers.
Harley is going to be confused for a while.
When I read this part, I looked at the date of the post, and realized I might be too late, and I am sorry that I am, but I think it bears mentioning anyway, in case it can help others who might read this thread. Animals seem to be very capable grievers, meaning that once they know the fate of their fellow pets, they seem to be able to go through the process of acceptance and healing quite quickly. If Harley did not get to see Diesel's body after he passed, then she doesn't truly know what happened, and doesn't have the closure that she needs to truly move beyond the confusion and depression. If she didn't see his body, then she goes to those parts of the house because she doesn't know where he is, and hopes he'll just suddenly show up there again like nothing happened. Death can be explained to human children and family members, but pets can only understand, accept, grieve and move on if they actually see their deceased loved ones after their passing. Otherwise, it is a mystery to them, never to be truly solved.
When I pass, if it's before my cat does, I have willed that he sees my body before he is moved to a new home. If I get other pets in the interim, it will be the same with them, and if any pass before the others, the rest will be given time with the body grieve. In fact we'll likely all take that time together.
Again, I'm sorry for your loss, and regret that I wasn't able to put this idea forward in time.