Dark siblings

He'd gone from a scrawny little kid to a tall pale-skinned teen with a slim, borderline ghoulish build. He looked down at himself and blinked at what he saw; black baggy jeans festooned with chains, a tight dark purple tee shirt and black elbow length fingerless gloves. I blinked, noticing he also now wore black nail-polish and dark eyeliner, while his shoulder length hair which had been light brown was now dyed jet black with red streaks framing his face. I glanced around, noticing my room was also different. All my stuff was gone and in its place was stuff that wouldn't have looked out of place in my sister's room and all the decor was in dark colours. "Huh," I commented, confused - why did this change too?