In the last LOST episode it is shown as they all die after Jacks dad tells him that But when they show them all back in states in earlier episodes everyone speaks to someone else So did they die?

In the last LOST episode it is shown as they all die after Jacks dad tells him that But when they show them all back in states in earlier episodes everyone speaks to someone else So did they die?
In the last Lost episode it is shown that everyone dies. Everyoneeventually does die on the island. When it shows them back in theStates in earlier episodes, these are sort of purgatory flashbacks.