Pokerus curing has nothing to do with how many EVs you have.
Whenever the game creates Pokérus on a Pokémon, the value assigned to
Y (days) depends on the value assigned to X (strain). Specifically,
the number of days will be set to X modulo 4 + 1. In other words, the
higher two bits of X are irrelevant to the "strain".
Strain X values Duration
A 0, 4, 8, 12 1 day
B 1, 5, 9, 13 2 days
C 2, 6, 10, 14 3 days
D 3, 7, 11, 15 4 days
Source for table and text: Bulbapedia.
Basically, Pokerus will wear off after a certain amount of days depending on the strain, which is generated randomly. So Pokerus will wear off Espeon either 1,2,3 or 4 days after contracting it.