she hasnt died yet
Season 5 Episode 12
Homer's mothers name is Mona Simpsons. We first learn this in the episode "O' Brother Where Art Thou". Homer also learns he has a Half-Brother in this same episode.
Mona dies in the books by getting pushed off a cliff by Spencer. Mona tried to push Spencer first because Spencer knew she was A but in the television show Mona survives the fall and gets put in a mental hospital.
I don't think Mona will try to kill Spencer in the TV series
Mona was in her late seventies when she died in an episode in 2008 (19th season).
Mona Brand died in 2007.
Mona Bell died in 1981.
Mona Caird died in 1932.
Mona Tyndall died in 2000.
Mona Rudao died in 1930.
Mona Fandey died in 2001.
Mona McBurney died in 1932.