Why is my husband having stomach issues?

My husband has stage IV colorectal cancer with mets to his liver. He had severe stomach pain and was hospitalized for a month. There was blockages but they turned out to be simply parastolisis. Again he went to the hospital with vomiting and was told the stomach and upper intestines were not moving food through as they should, but they don't know why because there does not seem to be a blockage. Is there anything that I should be asking? Do you have any idea why his stomach was not working but is now? He is eating and out of the hospital. Apparently it just started working on its own. These improperly working stomach and intestines are apparently going to be ongoing. Why is that?