My dog has a tumor and wont eat.?

Hey. My dog Molly,is about 12-14 years old. She's a bearded collie and the she has a tumor on her shoulder. For the past month she was iffy with eating and kept throwing up. We took her to the vets many times and the last visit a few days ago he found the tumor and weighed her, and shes lost alot of weight. She eats but throws up in the night and probably in the day too so she isnt getting her nutritions. Because she's old we're not giving her and operation or whatever they to do treat tumors. Instead the vet has given her some steroids and we're hoping within 10 days she will either put on weight or at least stay as she is, if she continues to be sick and loose more weight they're going to put her down. We got Molly when I was little and I picked her out, im 18 now and it kills me to see her like this. She's been such an amazing dog, she's had 2 beautiful litters and she did everything her self, we woke up and there they were suckling on her.Thats how amazing she is, she's never bit anyone or fight with our other 2 dogs, her daughter Jessi and Tasha, She's always been a well mannerd lady and its horrible and sickening to see her suffer like this. I know the best thing for her would be to put her down but I want to know if there is any hope at all for her :( We owe it to her to do the best we can to extend her life. Please could someone get back to me.