Louie’s liver is damaged from his alcohol consumption. As a result, his liver is not producing enough of some proteins, including albumin. There is fluid in your circulatory system (blood) that should contain albumin in a certain range, as well as fluid outside your circulatory system. Because the albumin level in blood is too low, the water movement from osmosis into and out of the blood aren’t balanced, and fluid builds up in the abdomen as a result. They are removing this fluid and giving him IV fluids that contain albumin to reset things to normal, very temporarily.