Good question! Since is not the Feywild, we're going to be treating all former connections of powers as the same. So, they exist, and their powers are still real, but a warlock would be the same as clerics and paladins. You can still attempt to petition your gods/patrons, but they won't be able to interfere with what the Fae here are doing. If the warlock were to convince some of the fae that they were chosen as someone worth the favor of an archfey, they might expect more of him, in fact.