so if I have Angelic Overseer out with some human tokens, and a Day of Judgement is cast, the overseer dies because the humans are destroyed at once, then the Overseer no longer has indestructible on it, right?
the overseer lives because as the DoJ resolves it still is indestructible. DoJ tries to Kill everything at once. So basically the overseer is trying to die at the same time as the humans but just cant because everything happens at once
When DOJ resolves, it will attempt to destroy everything. Since all creatures are destroyed simulatenously, at the time of resolution, DOJ will see an Angelic Overseer that's indestructible and a lot of tokens. It will destroy the tokens and fail to destroy Overseer. Then Overseer will loose Indestructibility, but it won't matter because DOJ is already gone.
Angelic Overseer