I am so sorry you are facing this, and he is feeling unwell.
I understand the vet was trying the antibiotics on the off-chance this may be infection....and there has been no change in his condition in 6 days. But is the Leukemia diagnosis definite?
Sometimes it is a fact that the dog is 'not ready to leave' but the body is not able to carry on. That happened with my own dog (who had Hemangiosarcoma) However, in the position where her body was in severe crisis, with a prognosis of only a few hours, at best, I had to have her put to sleep. It was absolutely our only choice.
It is one of the hardest things I have ever had to do. But I promised to look after her, love her, and see to her needs right to the end. And that final morning, she needed to leave her body, as it was in too much pain, with no further hope.
However, even in terminal illness, so long as pain and any discomfort is managed with medication, there is nothing wrong in choosing a period of 'Hospice Care at Home' for a dog. This will only work if there is someone with the dog at all times, the medication is working, the dog still has some good quality of life (eating, drinking, wagging, responding to loved ones, able to pee and poop outside, happy enough in itself) It is a bad choice if the dog has to spend hours a day alone while someone is at work.
Hospice care at home can be a beautiful experience in a way, as there can be something gentle and special about those last few shared weeks or days, so long as pain and symptoms are managed and the dog is not suffering.
There is bound to be some 'anticipatory grief' during these final weeks/days of course. But calm, and a loving atmosphere will help the sick dog. So it's important to be brave for their sake.
There will come a time of course, when the medication suddenly doesn't work any more, and upping the dose doesn't work, or a sudden crisis occurs, with no solution or treatment. Then it will be obvious that euthanasia is the best decision.
There are diagnostic procedures for Leukemia, but they are pretty invasive (bone marrow biopsy under anesthetic) The treatment differs depending on if it is chronic or acute Leukemia. But most likely will involve chemotherapy, as well as antibiotic therapy. But speak to your vet. Have a good dialogue with your vet about the possible options, the antibiotic treatment (do you need to give it more time? etc) and what he/she considers is the best way forward.
Thank you so much for responding. Last Thursday, Max was unable to get up from his laying position. He is home during the day by himself. At that point I realized that even though his mind was alert, his body was shutting down. I called the vet and we took him in, he had continued to gain wait, about 7 lbs since his ER visit which we knew was all fluid because all he was eating was boiled chicken. It had gotten to the point that I hand fed him piece by piece because he would eat it too fast and cough it all back up.
When the doc looked at him he said it was in his lymph nodes and he could tell by his eyes that he was in a lot of discomfort. We could drain more fluid but it would return in about 24 hours. At that point we made the decision to set him free from his pain. My husband and I were both with him when he passed. We've asked to have his ashes sent to us and we bought a stone to put his ashes in and set in our garden off our patio so he can be outside "smelling the fresh air and watching the wildlife". I miss him terribly and have cried more than I've cried for years.
Once again, I REALLY appreciate your words and kindness.