They weren't friends, but Severus would be hard pressed to say he had any friends, beside perhaps Dieter who was more tolerant of his dark moods and bullshit than any one living person ought to be. Even then, Snape would only openly admit that he very much liked his roommate under duress.
But maybe Neville was as close as someone like him ever tended to get. He was someone Snape tolerated more than others, anyway. He had a sort of quiet confidence about him, and he'd never held back from the truth when Snape had asked previously.
Even distracted with questions, Snape did not half ass the work, his fingers stained with dirt quickly. "Tell me about Sirius Black," he said after a sufficient amount of silence. It wasn't exactly a demand so much as a poorly poised question. He did not know, exactly, what kind of answer he was looking for.