(Findings on Tagpe (Biopsy result) He is diagnosed with malignant neoplasm; a life threatening tumor that spreads to the body quickly)

I took Tagpe to the vet earlier for further examination and to ask for advice and for some meds because he has been vomiting blood profusely lately, losing weight, and has been lethargic only to find out that the tumor has spread to his body and that his state is getting worse. Surgery is the most effective and ideal treatment for his condition but it would be very risky considering his condition and his chance of survival is very low. The vet suggested that it would be better to put him to sleep to end his suffering because he is evidently having a difficult time breathing and living a comfortable quality of life. Vet gave me time to think whether to have him euthanized or not as surgery is too risky considering the location of the tumor and his current state. I've been feeling lost and heart broken after this news. I've been looking for more opinions and advice on what I should do. I will give you guys another update of my decision soon.