Large hernia above belly button. Surgery refused. Can push some in so tummy is flat, I stand it returns straight away, can exercise help me look normal?

Several factors. There are hernias and there are conditions of weakened muscles such as rectus diasti. Depending on your muscle tone, weight, body habitus etc. you may be able to do some toning that will help, but often if very large, surgery may be needed. Not sure if the surgeon refused or you the patient? Best to see the surgeon and get recommendations on how to treat best. Good luck.
Doubtful. that exercise would have much of a positive effect, increasing intrabdominal pressure by straining from physical exertion could push it out more.