The only thing I've found that can help relieve the grief is puppy breath.

I had to put down my old dog Chaos a few months ago. He was the best retriever I'll ever have, without a close peer. When he was 10, he was diagnosed with Melanoma so I contacted the breeder and told him I needed another one closely related. I wanted to get the new dog while Chaos still had a chance to impart some of his wisdom on the young dog. As expected, the new dog picked up his house and blind manners from his mentor and needed very little input from me. On quail, he pointed immediately, backed with very little commanding and retrieved to hand (when I restrained Chaos). Thanks to modern miracles in the health field, Chaos lasted another two good years before the cancer overtook him. Putting him down was horrible but he need relief. I don't know how we could have managed the grief without the the distraction of the new dog and my little tracking weenie, Chloe. The new pup, Havoc, is now 2 and is showing real promise. He very biddable and has strong prey drive. He is an absolute fanatic about fishing. His favorite toy is the dummy launcher. He has very big shoes to fill but he is working hard to earn his place.

Very sorry for your loss. Get a puppy, not to replace your buddy but to honor him.