He crouched down and said, "Sorry, I let them take you... but I got your son to a safe place. They didn't notice I had him." 
Malfoy nodded and eyed the walls like they were closing in. He was starting to panic. 
"Hey, breathe... slow your breathing down. In and out... nice and slow," Harry said, and went to offer his hand to Malfoy, but Draco winced as though he thought Harry would hurt him.
Harry pulled his hand back and tried to calm him down. He stared at Malfoy, trying to rectify his memory of the once proud, pureblood aristocrat with this new version. Draco was now a nervous, cowed, but loving father who'd been living amongst muggles for four years, wandless. Harry would have never guessed it was possible. He now understood why Draco was so desperate at the safe house four years ago. He had a child and apparently believed he had no safe place to go.
"Malfoy... breathe... calm down...."
Malfoy's head came up. He was panicky again. "Please... I just need to know my son will be safe. I'll do anything! Anything!" he begged, adding a certain inflection to his tone.
Malfoy meant anything... including his body. Harry felt sick, wondering if that was how Draco had survived on his own. Malfoy still had good looks, though he was clearly underfed, judging by his weight, though the hoodie hid a lot.
"That's not necessary, Malfoy. I was raised in an abusive home. I could never let a child endure that, okay? So, calm down and don't offer anything to the other Aurors. They will take it," he said, bitterly.
Malfoy blushed and looked away.
"Do you want to sit at the table or stay here on the floor?" he asked.
Malfoy wouldn't look at him. He just trembled. 
"Come on, get up," Harry said and half-pulled Malfoy up and into a chair. "There you go. Now... where do you want to start?" 
Malfoy flinched hard and didn't answer. 
"Look... it's just me and you. No one is watching. They will make you tell them everything anyway. They'll use Veritaserum." 
Tears flowed out of Malfoy's eyes again, and he started rocking back and forth. 
"Hey, calm down... and listen, please! I'm probably the only one who will help you, but I have got to know what happened, alright? You need to talk to me before Robards gets here and rips me off the case, because I won't be allowed to see you after this."
Malfoy processed this or, at least, came to terms with it. 
"What... what do you want to know?" 
Harry debated his words and what had been gnawing at him. "What did Voldemort do to you?"
Malfoy recoiled like Harry had punched him. His grey, frantic eyes met his. "You don't know?" 
Harry shook his head. "Your file is redated. I was in training when the Death Eater interrogations occurred. The public trials did not mention you... but the other Aurors... they make comments about you, and I don't know what they mean."
Malfoy lowered his head. "I can't... please." 
Harry heard the distress in his voice and nodded. "We can take our time... start off on easier topics? What about your son?"
But Malfoy flinched again. More tears dripped down.
"I'm sorry, but I need to know who his mother is. Is she still alive?"
Malfoy gave him a strange look. "Mother?"
"The child's mother? If there's a reason why he can't go to her, then I need to know."