I have a 15 year old mini dashund that was recently diagnosed with a cancerous tumor in one lung. To limit her coughing she was put on codine. She has progressively lost her desire to eat. Other wise she seems OK. We've given her steak, liverworst, peanut butter,. Each time we think we find something to keep her nurished, she won't eat it again. We've stopped the codine but she still won't eat. She drinks water OK. Is there anything I can give her to enhance her appetite? I just want her to be comfortable in her last days with us.