Please advise needed

[Snickers]

Hello I am looking for some advise please. My 8 1/2 year old yorkie snickers has been diagnosed with a spindle cell sarcoma in his liver today. Before I continue I will go back to August, he was feeling really loe energy so I brought him to the vet, his red blood cell count went from 30 to 10% in 2 days. I was referred to a speciality vet that day, they did a blood transfusion on him and and u/s and found a spindle cell sarcoma in his intestines. He had surgery a day later to remove the tumor. They told me they got it all out and margins were clear. They said it was a type of cancer that did not tend to come back. They recommended getting and ultrasound in 4 months, so that brings us to this week. He had the ultrasound on abdominal and they found a 6ml tumor in his liver. They did chest x rays also and was clear. They did an needle aspirate and I just got results saying its a spread from the first tumor. It's a spindle cell sarcoma. The doctor today referred us to an oncologist the talk about a drug not chemo. I quess I'm just looking for some advise if anyone has went throught this. What would you do if it were you. I don't know the name of the drug but she said dogs do well on it. Do you know how long he would live if we did not do any treatment. I do not want him in pain but I don't want to put him through drugs if its not going to work. Any advise is appreciated. Thanks