User blog comment:B214/Volume 22 spoilers/@comment-201.215.165.7-20170112030400/@comment-30924344-20170112114428

Lifespan doesn't matter to Issei anymore, it's limitless thanks to his body being made from a dragons flesh and power; dragons can't die due to old age and they can be revived just only the evil dragons can self revive so Issei can be revived too most likely.