I am SO FASCINATED by what is going on with her dad. I am assuming he could also see spirits, like Miko does, and one reason he's sticking around is to keep the house a safe space for her
In one of the previous chapters, we see a picture of a black haired orphan with the Godmother's Master. My hunch is that is her dad, and that spirit with him is helping guard the family, it might even be a guardian spirit.
EUREKA! I just had a revelation! Dad must also have been able to see those ghosts when he were alive, and i think he was a part of that men in black group. The elderly man, whose face we saw, might even be Miko paternal grandfather!!!!!