You clearly haven't seen my rants about that problem
Tang Shen - Dead - Murdered by the Foot
Turtles have a fairly complicated relationship with their father, which is going sour.
Casey's mom - Dead - Cancer
Casey's father is physically and emotionally abusive
Angel's mom - Dead - Hit by a car
Dad barely shown?
Alopex's mom - Dead - Forest fire set by Saki
And so is the rest of her family
Saki's mom - Never shown, probably dead in Secret History of the Foot Clan
Sour relationship with his father
Krang's mom - Never shown, probably dead at the time of various flashbacks
Where do I even begin with Krang's relationship with his father?
Pantheon's mom - Not discussed, probably dead, but is implied to be a Phoenix in a painting so that might not last
They're terrified by the idea of their father's return to the mortal realm, save for Kitsune
It seems like April's mother is the only one that's alive, well, and present in the story. And not only that, has a healthy relationship with both of her parents.
Karai's parents are both alive, but she doesn't seem to talk to them anymore.
It's kind of a disturbing trend of "dead mom, bad relationship with dad" for a story that's "All about the importance of family". I mean, Casey has the spirit to be a good dad, but I'd rather not have that at the expense of Jennika/Gabrielle dying in childbirth. Especially with her being as bad@$$ as she is.
My feelings about the 7/9 mom characters being dead (or potentially) basically feels like this