Dad has a million reasons why he has to leave the hospital, but not ONE makes sense. What do I do?

My dad has been on an emotional and medical rollercoaster. He was in the hospital for 5 days, discharged to rehab for 3 weeks, and then back in the hospital for 2 weeks. He finally has a diagnosis (bladder cancer). Ugh. Dad has always hated doctors and hospitals - even when he was just a visitor and not a patient! On most days he makes complete sense. Even when he questions his doctor about his condition, he's logical and well versed. BUT shortly after the doctor leaves (and usually after the bomb has been dropped regarding something about dad's medical condition), he shuts right down and then within minutes he collects his things, looks me straight in the eye and says, “ok let’s go grab some dinner.” Wha???????? Then after that he says (straight as an arrow mind you), I have things to do at home, I have to pick up my car, I have to get to work, etc etc etc (none of which is true). I try to calm him down and make sense of the situation - asking him, what are feeling right now? I understand that you’re upset, or anxious, or whatever! But then he gets angry and just unravels like a caged animal. Tonight’s episode was a lot more serious than others. We met with an oncologist, but rather than telling me that he’s angry or scared or just anxious, he started making up stories over and over about what he has to do and why he has to leave. It’s so heartbreaking that I can’t get through to him. I “think” he understands that he’s making things up but I seriously think he’s so desperate and scared, he’s trying anything hoping he’ll outsmart us. What do I do???