She returns in person in season 9 , angry at her son for putting her away , seemingly trying to kill him .
It 's later revealed that she has a history of mental illness which Dan 's father hid from him .
She returns in person in season 9 , angry at her son for putting her away , seemingly trying to kill Dan .
It 's later revealed that she has a history of mental illness which Dan 's father hid from him .