What is the term and conditions of cancer drug treatment and service of IPs after the cancer drug list changes?

My family member is undergoing cancer treatment for the past one year and half. Fortunately he has IP with rider to cover the medical expenses. However recently our agent informed us that his cancer treatment claims are only eligible for reimbursement up to 365 days after his most recent hospitalization. The outpatient cancer drug treatment and service comes with this clause. The IP is one of the companies (not name the company here). I am confused, the differs from my understanding, which I believe outpatient cancer drug treatment / service is separated from pre/post hospitalisation terms, even after cancer drug list change. But he insistes and shared with me the official doc provided by the claim office. Could anyone know about the details of the terms?