I am so sorry you've lost your beautiful boy at such a young age. Saying goodbye to our beloved pets is always awful, but you both were tragically robbed of many years of memories. I can't imagine how difficult this must be for you and your family. I wish you all peace and healing as you grieve.

After you've had some time to process, I would recommend reaching out to the breeder with the veterinary records. At the bare minimum they should know what health concerns are in their lines, and it may help another family avoid what you're going through. Cancer is very common in Goldens, but even moreso for English creams and other newer color variants. Best case scenario the breeder will have their dams and sires undergo genetic testing and stop breeding dogs with health concerns, but if not, they deserve to be dragged for knowingly breeding and placing dogs who are more likely to live short, painful lives.