Mary was in the hotel too and she's not dead unless she died while Kevin was poisoned. SHES "brain dead" so her consciousness is trapped there
also, virgil told kevin he would be there to guide him, so its possible kevin just dreamed it.
the metaphors though
kevin coming out of the dirt like regina was talking about the birds
so has it been threee days later? if it was three days later that he was buried in the ground i dont think theres anyway he dreamed it all, like how people think virgil gave him something that makes you look dead for a few hours
thank you lindelof