How can I tell if my dad is getting better or worse from the chemo or cancer?

My father age 79 ( I am 53) was diagnosed with Lung cancer, stage 4, spread to both lungs, stomach and bone in shoulder, 5 months ago and has moved in with my husband and I. Dad is on his 4th Chemo, but this time his appetite has almost completely gone, which makes it rough because he is also a diabetic, has one kidney and has a bad heart. Trying to get him to eat enough to keep his sugar level within safety levels is a challenge. I have to try all the persuading I can, to get him to take in small amounts, he hates water. I would say he eats about 300 calories or less a day, in food or beverage. less than 8 ounces of liquid a day. He has diarrhea, allot and no bladder control anymore. Dad looses his balance allot, memory and tosses and turns all the time, and in pain allot. We never had a family member with cancer before, and I seem to get all sorts of different info. The doctor has not given us any time table. Is this recent bout with not wanting to eat or drink, to the severity he has taken it this Chemo round, normal? or he is progressing into a finale stretch, of his life? how will I know? He would be too embarrassed for Hospice, I fear, plus I have 2 dogs, I don't know how they would be with strangers coming and going. and I am doing ok for now. at first he has lost 65 pounds before they discovered the cancer... in 6 months prior... When he first moved in with us, he gained 25 pounds of it back, in 2 months, he was eating pretty good. nauseated now and then but eating and drinking. But now it is like a switch got turned off, he has lost 12 pounds in the past month, and this past Chemo, last week has just about shut down his consumption. They did a brain MRI and liver-gallbladder-pancreas scan, and they told me there was no cancer there. I am hoping they are not keeping the truth from me. His tumor on his one lung is pressing on his vocal cord nerve, and he cannot talk well. They are -planning- 2 more chemos in 2 months time and then go to radiation. I don't even know what to expect for that, he is so frail, how can I tell if he is getting better or worse? what is the Cancer, and what is the Chemo? I've been to just about every website out there, they all say the same stuff. I need personal input. Thanks so much. -Sherrie