RAMALLAH, West Bank — Saeb Erekat, a leading voice of the Palestinian cause for decades, now finds himself battling for his own health along with that of the long-ailing peace process.

Both came into sharp focus this week as headlines in the Israeli news media blared that Mr. Erekat, the secretary general of the Palestine Liberation Organization and its veteran chief negotiator, is suffering from pulmonary fibrosis. He is waiting for a lung transplant, most likely to be carried out in the United States or Israel.

That news coincided with a rather bleak assessment of the peace process by Jared Kushner, President Trump’s son-in-law and special adviser, as revealed in a leaked audio recording. In remarks that were intended to be off the record, Mr. Kushner told congressional interns on Monday that the administration was still “thinking about what the right end state is” and that “there may be no solution” to the conflict.

In an unusual statement on Tuesday, Mr. Erekat criticized the Trump administration for not articulating support for the two-state solution — the internationally accepted principle for resolving the Israeli-Palestinian conflict since the 1990s — and for failing to compel Israel to cease settlement activity. He described the administration’s silence on these issues as an obstacle to a resumption of negotiations.