My father passed away in October of 2006. He was diagnosed with stage 4 stomach cancer (linitis plastica) in December of 2005. My father was 66 years old when he passed away. He did have trouble with ascites with his cancer. They did drain his ascities one time. The chemo will eliminate the ascites if it is working correctly. Dad had a large build up of ascites at this death, he was very bloated. Our Dr. told us that the general rule is to drain it only at the patients request (i.e. it is too uncomfortable for the patient).
My dad hated the protein drinks such as Boost. If you can get your dad to drink them that would be great as it is important to get as many nutrients, proteins, and calories as he can get. Stomach cancer and chemo both mess up a persons sense of taste. Your dad may be very different from mine. My dad could tolerate water and milk well. He liked cereal and he ate of all thinks black-eye peas alot. I was able to get him to drink Carnation Instant Breakfast drinks.
May God bless you all during this tough time.