I have been listening to all the speculation bouncing around about the significance of Flocke comparing crazy Claire to his own mother to Kate. One thing that has been very enlightening is viewing the earlier appearances of MIB as Christian and others in previous seasons. After watching these episodes you can speculate the MIB takes on some of the personality and memories of those he uses as templates. This probably gives him a quick background into those people around him and contemporary information in order to communicate and influence people.
Back in the season 4 episode, “cabin fever” MIB appears to Locke as Horace Godspeed and Christian Shephard. Locke learns he is “Chosen” and that to save the island he must move it from Christian. By all accounts MIB has already selected Locke as his “loophole”. Horace comes to him in a dream and tells him he is building the cabin for his wife and waiting for Locke there. I do not necessarily believe that MIB literally meant HIS wife, but Horace’s.
In season 5’s “This place is death”, Locke has fallen into a cavern below the well that is the frozen wheel room and suffers a compound fracture to his shin. Christian Shephard appears and tells Locke that he must find everyone who left the Island and bring them back. Locke fulfills his destiny and turns the frozen wheel. When Locke asks about Richard's statement that he would have to die, Christian responds, "That's why they call it a sacrifice." He instructs Locke to fix the frozen wheel saying it's off its axis. Locke pulls the wheel back into alignment as Christian says to say "hello" to his son. Locke asks who his son is as the room is engulfed by light. Does this mean that Jack is MIB’s son? Of course not, what it means is that there is a mingling of the hosts memories and personality with MIB that he can use it to manipulate people. I believe Flocke is referring to Emily Locke in his discussion with Kate.