I just found out my boyfriends dog has blood cancer. Anyone ever had a dog with the the same diagnosis?

My boyfriend is so emotional right now and cant think of what to do. I dont know how to help him. He has a crocker spaniel that s 9 yrs old. He hasnt been eating and his urine had blood so the dogs test just came back and he has a growth in his stomach and blood cancer and needs a blood transfusion. The doctor doesnt know what will happen to the dog after the tranfusion and we dont know what to do : (