When R&B singer Luther Vandross died on July 1, 2005, two years after suffering a massive stroke that kept him at a rehabilitation center for the rest of his life, no one felt the loss more than his mother, Mary Ida. A retired nurse, she raised her four children alone after her husband's death in 1969. Luther, the youngest, whom she affectionately nicknamed Ronni, was her last living child—and all of them suffered from diabetes. In her first interview since her son's passing, Vandross, 82, spoke to PEOPLE's Mark Dagostino about Luther's final days, his legacy and how it feels to hear her son's voice again on the two previously unreleased songs included on the greatest hits CD, The Ultimate Luther Vandross, due Aug. 22.

I feel sincerely that God had some connections with my son. The winter before he had the stroke, I noticed that he was putting things in order. Too much in order. I was living in Connecticut, in a 10-room house, and he called me one day and said, "Momma, I don't like you being up here by yourself. I want you to think about moving to Philadelphia." I started laughing, and he had the best laugh, and I said, "I like Philadelphia to visit. I don't know how I'd like to live there." But he said, "Think about it. You're here by yourself, and you don't need to be by yourself." I just feel like he was telling me something.

Not long after Mary Ida moved closer to her family in Philadelphia, Luther's housekeeper and assistant found him collapsed on the floor of his Manhattan apartment on the morning of April 16, 2003. Doctors would soon discover that the singer—who had struggled with diabetes, hypertension and weight fluctuations for years—had suffered a burst blood vessel at the base of his brain. He spent two months in the hospital going in and out of consciousness before being moved to a rehab facility in New Jersey, where over the course of the next year, his condition improved dramatically. On good days he could walk with little assistance. He talked, joked with friends and even sang at times. But in his final months, the progress seemed to end.

For two years I went every Sunday and any other day that I could get there. The Sunday before he passed, I had a premonition that I was losing him. That was the saddest moment of my life. Here I am with one child left out of four, and to see him drifting away ... I told the nurse, "Please get him up. I want him to have dinner with me." So we got him up and he had watermelon and corn bread—his favorite food—and he was talking just like you and I right now. And I said, "How do you feel?" And he says, "Okay." I said, "Ronni? Do you know I love you so much?" He said, "Yes." I said, "Please do me a favor and get well." And he never answered me.

I said, "Ronni, I haven't sang this song to you since you were a little boy." And I started singing: "You'll never know just how much I love you / You'll never know just how much I care ..."

When I stopped, he said, "It was okay." I said, "Okay?! You know something? I have to duck from record companies trying to get me to sign up." And he said, "Well, keep duckin'!" And we laughed. But when I left, and I saw him watch me, I just had a feeling that was the end.

That Thursday, my sister and I were in the kitchen, and I said, "Helen, I hear death bells. I'm losing my son." And on Friday I just couldn't stop crying; I cried myself to sleep. And when I woke, my niece Brenda told me, "Ronni died about an hour ago." And I screamed. I said, "Oh, Lord. My last child. Help me to understand." I remember that very well. All I need to do is understand.

God knows how empty my life has been since all of my children are gone. I prayed for understanding, and soon after that, I got several engagements to speak different places. Each time, the mention of diabetes comes up. I'm not a doctor or a nurse. But I beg people, please, have yourself tested. [See box.]

I miss him so. Nobody on earth knows how I miss my children. I went to the cemetery Saturday and I looked at his grave, and I kept asking, "Why, Ronni? Why?" I just couldn't stop crying. That's why God gave us tear ducts, you know? You're supposed to cry.

Once in a while I listen to his music, but I notice what it does to me. It tears me apart. Especially the older ones that he wrote when he was a boy coming up, like "Never Too Much." [With the release of the new songs] it makes fans feel like he's still around. People come up and say, "I saw your son on television last night," or "Your son's latest record is pretty!" He touched so many people. Remember one thing, most of all: that his songs were trying to tell people to bring love back into their lives. Audiences loved him. And he loved them too.