Even though they are the same age, Nina has always had a personal incentive to be overprotective of her brother. Whether it was because he processed things different than most kids their age, or the fact he seemed to be oblivious to danger even when he may be outmatched - whatever the case was, Nina was always there to help bust him out of harrowing situations. However, even she couldn't be everywhere at once and Michael would get in trouble and require some stitching up. She'd naturally rag on him a bit about it, but she'd always stay by his side to help him on the road to recovery - even if he wasn't outwardly appreciative of it.
