My Father Had Triple By Pass Surgery 14 Years Ago.

My father had triple by pass surgery 14 years ago. He is in the hospital now and they did stress test and echo test. I was told his heart is working at 22 to 25% capacity. They plan to do a cathe test today. He is 83 years old. My question is what type of questions should I be asking to get answers. I would like to know if they find blockage and fix it will that make his heart work better and how long does he have if your heart is only at 25% and what signs should I look for.