Based on Bernece story about Jimmy, what do you think of him and his behaviour towards Ren?

Bernice tells her story in "The Year of the Flood". Is this the story you're referring to?

She'd had a roommate like that at first, plus he'd been an animal-murderer because he'd worn leather sandals. Though they'd been fleather. But they'd looked like leather. So she'd burnt them. And thank God she didn't have to share a bathroom with him any more, because she could hear him doing sexual things with girls practically every night, like some degenerate bonobo/rabbit splice.

'Jimmy,' she said. 'What a meat-breath!'