O Bharata, a superior on being addressed as 'you' dies (at heart). Therefore, you do addressed the much-respected Yudhishthira as 'you.'
त्वमित्यत्रभवन्तं हि ब्रूहि पार्थ युधिष्ठिरम्। त्वमित्युक्तो हि निहतो गुरुर्भवति भारत॥