Hello DC
What an amazing dog is Mr Bob! The pictures show his soul shining through his eyes. You and he were one of the rare and lucky human-animal pairs to share a single soul. You carry part of Bob's soul and he carries part of yours - always and forever.
Treatment .... absolutely. It gave him a longer life with a good quality - and more time for you guys to bathe in each other's presence. I lost my Gretta (the kindest chocolate lab who ever lived) 13 months ago. She was always on the borderline of having CUshing's but the screening tests were always "can't determine" and I didn't want to put her through the chemo just to get a definitive diagnosis. I can SO relate to you saying Mr Bob walked 2 blocks up until 3 weeks before his passing. Gretta walked, trotted and even ran sometimes up until the last couple of weeks. She crashed in one day - a collapse of the spinal cord (whatever that is - and I DO NOT want to know) - at 6 AM she went on our normal 10 block walk, by 10 am she could barely make it around the block and by 3 PM she could barely stand up. At that point I rushed her to the University Vet clinic (which thank god is open 24/7) and the next day I had to make the fateful decision.
One thing is for sure, DC: love is forever. It does not fade or die - if it is true love. And your love for Mr Bob and his love for you is THE strongest kind there is in the universe. It will never diminish, let alone die. My vet's words were, when he heard of Gretta's passing "She's in a safe place now." ANd this from the ultimate man of science. So ... if he believes it, so do I. An old Black preacher taught me that faith is a choice - and I absolutely choose to believe that Gretta and Mr Bob and all creatures great and small do live on - in a Perfect World.
Bob is there and at the same time right beside you. (You can do that if you aren't encumbered by a physical shell

) He's on his job just like always: watching over you, guiding your steps, reading your heart, and, most important, LOVING YOU. And he feels your ever-so-strong love at every moment. He's joined Gretta and Trevor and all the other creatures in the Perfect World. Gretta is on the welcoming committee so she's already met Mr Bob and they are trading stories about their mom and dad - newbies always get first bragging rights!
Please be gentle with yourself and the rest of your "pack". They need you now and you need them. Your only job during these first few months is to breathe in after you breathe out - seriously. Once you have that mastered reliably, you can worry about the rest (which doesn't matter anyway).
Missing a soul-dog, too,
Gretta's mom