I believe we talked about this before. From what his dad said, she might not be a ghost as we all assumed so she most probably is an angel, a servant to Qetesh
We did and we never reached something that could be called a conclusion.
Tinkerer is the only one who could find one, but as we established before this entire "meet the Family" act was improvised as Tinkerer never did intend to actually include this part to the story... high demand of the Patreons made him change his mind.
His attempt to make the mother a Ghost could be to avoid her as a love interest, but what's far more likely will force him into coming up with a story to revive her and give her some kids of your own... mother/son incest seems to be one of the highest demanded fetishes these days