Pleural Effusion

My 82 year old father undergoing Folfox and Avastin, going on his 8th treatment, now has a moderate right pleural effusion. The doctor says he will need to have it drained and stay in the hospital for 3 days. Has anyone had anything like this? Wondering whether this will really knock him down. It's so difficult to know what to do, it is making it hard for him to walk very far with becoming short of breath. We are going to get a second opinion since the first doctor we went to, Dad did not like at all, He was very pushy, short, curt and didn't take any time to explain what would happen if we waited to have the fluid drained. He just walked in the room and said your fluid around your lung needs drained, lets get it scheduled!!! Just really nervous about all this, the chemo is hard enough on him.