Mom is dead, so unless the MC finds a way to bring her back, she's out of the picture.
Then again, I got the feeling there were some sexual tension between mother and son before she was killed and this is a world which bears many resemblances to ancient Greece and according to their mythology, dead people could be retrieved from Hades, the death realm (but it was difficult as fuck and not something mortals were supposed to do). Considering the MC is already consorting with gods and demons, who knows what might be possible in the future?
And then there is this shape shifter who considers the MC her/its master... I guess she/it could take the shape of the MCs mother? Maybe some other actor might have that ability as well, or the ability to haunt the MC in his dreams and there take the form of his mother? I guess not quite the same thing, as it wouldn't be his real mother. But for him it might feel real until it's revieled that it's not.
Seems the setting gives many possibilities. But as of now, the mother is dead, so don't bank on her becoming romanceable.
