He added that Mustafa, a civil engineer, was very close to him, and that he was an intelligent boy who liked to argue with him.
He said his family had kept Mustafa’s accident a secret from him when he slipped and fell in front of the restaurant and hit his head on some bricks.
"Only several hours later when my son was already in the hospital did I know what had happened to him. It’s a tragedy for us, but I am proud of him."
"At first, we were worried for Muszaphar when he went to space but right in front of us, another of our loved one died," he said.
The father said he built a house in the same compound for Mustafa, his wife and two children.
"I wanted him to be close to me. That is why I built the house for him," he said.
For him, Mustafa was the most intelligent of all his five sons, he added.
Deputy Prime Minister Datuk Seri Najib Tun Razak turned up at the house at 11.30pm to offer his condolences. He comforted the family on their sudden loss.
"This is a personal test for him (the father) and his family. With the grace of God, I hope they will brave through this period," he said.
Najib said the Government would arrange for Dr Sheikh Muszaphar to arrive at the KL International Airport at 2pm today to attend the funeral in Makam Tuan Haji Syed, Seremban.
"We'll arrange to take him to Seremban to be with his family."
The welcoming home celebrations for Dr Sheikh Muszaphar would also be postponed three days after the funeral, he said.
In a telephone interview from Moscow, the Angkasawan said: "When I went to space I found my life. But when I returned, I lost the life of a loved one."
He said he received the unexpected news of the death of his brother, the second youngest of the five brothers, with shock.
"I loved him. We were all so close and it is very difficult for me. I feel an emptiness," a grief-stricken Dr Sheikh Muszaphar said.
The Angkasawan said he had just completed his rehabilitation at the Gagarin Cosmonaut Training Center in Star City after landing on earth on Oct 21, and was rushing to return home.
"I hope I make it to the funeral. I want to be with my family at our difficult time."
He added that it was supposed to be a joyful moment for Malaysians as well as his family after his successful and historic mission to the International Space Station on Oct 10, but tragedy befell his family.
"But I take it as a test from God, that He wants to see how I can handle it. I have no regrets about going to space and this loss is something I just have to face," he said.
Dr Sheikh Muszaphar thanked the Universiti Malaya Hospital and Hospital UKM doctors for doing all they could to save his brother.