How Many Dead Grandmas

how many dead grandmas? one idiot calls into work saying their grandma died & the next week that same idiot tells their professor that they missed class because their grandmother died & the very next week calls into work saying their other grandma died & a day later tells their prof that their other grandma died & the classmates & coworkers talk amongst themselves saying that the same idiot held other jobs before this one & frequented other classes before this one overflowing with dead grandmother galore--- how many dead grandmas can one idiot have?