I don't think they can die because the body didn't. I feel that they just go dormant because they are not needed anymore.

I get parts that wake up after years to decades that have no present memories. Seems kinda funny because they like freak out and they are like here again...like Hillbilly....from a decade ago....woke up and had a blast noticing that we were still driving the truck he bought back then as we are and have been living states and lifes away....then to say his farewells because this isn't his time....just triggered out and gone again....accent and all. I'm sure if chance maybe....he can/will emerge because some memories of his at times surface if we weed through the layers of past life...if lucky.