My grandfather was saying "help!" through an oxygen mask on his face for several days before he died. I didn't know how to respond because there wasn't anythin

My grandfather was saying "help!" through an oxygen mask on his face for several days before he died. I didn't know how to respond because there wasn't anything we could do. He struggled like this, in pain, but at the very end he had an expression of complete joy and peace that was really moving to me. I was very close with my grandfather and felt I could understand what he was feeling without any words. My interpretation is that he experienced some type of complete acceptance of death and/or awareness of something beyond death. It was really beautiful and comforting to see, especially after watching him struggle for days prior to this.