If you really think your dog is not going to bounce back this time, I would go ahead with the euthanasia.
Here is one service (note I am not affiliated with this vet nor have I ever used them, I just googled for you):
http://www.novamobilevet.com/ They have a home euth service and say that the choice is yours and the doctors will respect that, so I'd imagine you won't get any pushback from them.