I'm so sorry to learn of your loss of Ben. I'm not on the forum as much as I used to be, so I didn't know he was sick, but your words resonate with any of us who have nursed a dog through an illness (or age) that requires special treatments and accommodations, strict schedules, food and medicine prep, etc. You don't realize how much of your routine is focused on these things until your pup is gone and you suddenly find yourself stunned by the change in your routine.
It was a long time after he was gone before I stopped listening for our dog stirring at night when he needed assistance. It was very hard to not reflexively do certain things at certain times, etc. When those reflex actions occurred in the early weeks, the initial reaction was immediate sobbing (I completely understand your "dehydration" comment - so true!). Later, I felt guilty when I started sleeping in longer during the week because I didn't have to set aside a block of time for special food and medicine prep. The range of emotions is unbelievable and exhausting. And you're not alone in your desire to remember his scent. One of the saddest days for me was when his blankets no longer smelled like him, despite my not washing them.
I also understand what you said about the condolences on this forum giving focus to your tears and grief, even if the messages were simply to repeat, "I'm sorry for your loss." Without a doubt, each expression of sympathy posted by members touched me and brought more tears, yet to this day I'm so grateful for them. Sometimes you can't enough comfort or validation from your circle of neighbors or co-workers, even family. You may wish to print them out and save them with Ben's special mementos. I did that, and I've re-read them more than once.
It sounds like Ben's life with you on your farm was truly heaven on earth - something most dogs, no matter how loved they are by their people, ever get the joy of experiencing. He'll surely have lots of love and joy to share with his new angel friends. My thoughts are with you and the rest of your household as you adjust to Ben's absence. Take care.