I'm so sorry to hear this, Wii. Went through it with my Mom 5 years ago. She opted for Raditation and Chemo. She still died 3 months later. I wished we'd just made her comfortable but it really was her choice.
Be strong. Your dad, your mom and your daughters will need you to be. And spend as much time as you possibly can with him. You will never regret it.
I'm glad he came out of the surgery so well. Hang in there.