Did my father feel pain?

My father was in kidney & liver failure and he was suffering from diastolic heart failure. When my father fell ill, he returned home and I cared from him until his last breath. We set up home hospice who made him as comfortable as they could with Morphine, Ativan and oxygen. Four days before his death, he could no longer speak but he could feel discomfort if moved. Three days before his death, his eyes glazed over white. They had a marbled table top pattern. I could no longer see the color of his own eyes. I asked the nurses who seemed confused about it. And were only familiar with a cloudy/glassy eyes. A day before his death, he shed tears a few times. But the day of his death, no tears. His blood pressure before death was 50/20. His breathing was shallow and spaced out by 16-30 second apart. When he past over, he didn't gasp for air; he took one last breath and his pulse didn't stop until 2 minutes after that last breath. A minute into his last breath, he clinched his hands and his chest tightened. His face didn't grimace but seemed to tighten. My fear is he was suffering. That he felt he couldn't get enough air. I keep having nightmares of my father in pain... he keeps dying in my dreams and it always starts off good with us believing we beat this and then he's dying again. I can't stop thinking of his death. I feel darkness. What does the clinch mean? With a blood pressure so low, could he still feel pain? What does the marbling of his eyes mean? Can anyone help me, please?