"David is amazing," Madonna, speaking via satellite from a TV studio in London, said during a half-hour interview that taped Tuesday and airs on Wednesday's Oprah Winfrey Show.
"What really surprises me is how great my children are with him and how he's transitioned so easily from living in Africa in an orphanage to living in our house," she said.
Madonna, who has two children – daughter Lourdes, 10, and son Rocco, 6 – and husband Guy Ritchie, traveled in early October to Malawi, where she is funding humanitarian initiatives.
David, whose mother died shortly after his birth, was brought to London last week after the Ritchies were granted an interim adoption order.
"The doctor found he had pneumonia. He was given an injection of antibiotics and a course of antibiotics, which he took the entire time we were there. He's still a little bit ill. He's not completely free of pneumonia, but he's much better than when we found him."
Madonna also denied that Malawi's adoption laws were bent for her, as some human rights groups have claimed. "If only my wealth and my position could have made things go faster," she said. "I assure you it doesn't matter who you are or how much money you have, nothing goes fast in Africa."
She said a social worker warned her that "there were no known (adoption) laws in Malawi. They were more or less going to have to make them up as we went along. She did say to me, 'pick Ethiopia, go to Kenya,' (but) I'd already started my foundation, Raising Malawi. … It seemed absurd to me to adopt somewhere else.
"I did have my heart set on David," she continued, but because she knew she might not be able to adopt him, "I did meet other children that I was open to adopting, so if it hadn't worked out with David, I would have considered any of those children a blessing."
She also put to rest rumors that Brad Pitt and Angelina Jolie persuaded her to adopt a child in Africa: "I've never had any discussions with Brad or Angelina about adoption. I've actually never met Angelina Jolie."
Madonna says she met David's father, Yohane Banda, in court. "There is a customary law, a tribal law that if you adopt a child you have to get permission from some living member of the extended family. … No one from (David's) extended family had visited him since the time he arrived. From my perspective there was no one looking after David's welfare. The minister of children's welfare went and found his father, asked for permission, told him exactly what I wanted to do."
Banda needed to give written consent to the adoption, Madonna said. "He came into the courtroom with my husband and I and he looked into my eyes and said to me that he was very grateful that I was going to give his son a life and that had he kept his son with him in the village he would have buried him. I didn't really need any more confirmation that I was doing the right thing and that I had his blessing."
Ultimately, she said, "My goal is that I will give David an education and a chance for a better life. What a better way for David to go back and help his own people and help the Malawians and be a voice for his country than to first have a life?"