Is it normal for an 8 year old to sleep with her parents?

My parents still have my sister sleep with her. She's 8. Now she's too scared to sleep on her own. Is this normal? They keep saying it's 'what people do nowadays' or 'her rooms not ready'. I think they just don't want to deal with her crying and tantrums on having to sleep in her room. Or some sort of baby-coddling thing.