。。。
Good morning, Haruki-niisan. You've got bedhead.
Literal
Good-morning. Haruki-big-brother. Bedhead attached [progressive-てるよ].
寝癖 (ねぐせ) 'bedhead / sleep-caused hair dishevelment' is a common everyday compound. ついてる is the casual contraction of ついている 'is attached/sticking.' The combination of おはよう (casual morning greeting) + 兄さん (older brother address) + a teasing observation creates a natural sibling-morning-dynamic scene.