It was Obito's final moments and Madara was explaining how badly he'd screwed Obito over from the start, having arranged Rin's death using her and the Kiri ninja who'd captured her in order to set Obito up.
Two words in Madara's explanation stuck in Obito's mind as he slid towards oblivion and the Black Zetsu took over. Those words were "Elder care". Something he'd been rather good at when he was younger.
Madara had gone and turned his life to shit because he'd wanted a fucking sponge bath.