First, what do you mean by surrender? Are you surrendering him, to a shelter, and hoping he will get adopted by a nice family with a farm? If so, it won't happen. Absolutely do NOT do this. He will go directly to euthanasia. Old dogs especially are not going to be kept to be adopted out. There are too many young, cute puppies that need homes, and the cost of keeping an older dog around is too much. If it's a no kill shelter, his QOL will not be better in a kennel until he dies.

If you mean you are taking him to be euthanized, then take your other dog with. Both of you stay in the room when it's done, and let him see his friends dead body. Animals know, and it will be much easier for him to know what happened to his friend, rather than think he just left him. There will be an adjustment period, and you'll have to pay extra attention to the one you still have.

Also, as someone else said, if you are euthanizing, see if there are mobile vets in your area, who come to your home. It was honestly the best decision when we had to put my 19 year old cat down. She was comfy at home, and not panicked and in a clinical setting with all kinds of weird smells, people, noises, and all the other scary things. They handled everything, including her cremation, and notifying my regular vet for me.