Mama Riley

Mama Riley is the mother of Dewey and Tatum Riley. She only appears in Scream (1996) and is unmentioned in the sequels.

Scream (1996 film)
Mrs. Riley told Sidney Prescott, her daughter's best friend, that there was a call for her. She asked Tatum how Sidney was coping with her recent attack and soon rushed to Sidney's side when she panicked on the phone. She called for Dewey's help, concerned that Ghostface was harassing Sidney.

After this event, Mrs. Riley's only daughter is murdered by Billy Loomis, the revealed killer.

Scream (2022 film)
The fifth film reveals Mrs. Riley chose to cremate her daughter, Tatum's corpse after the events of the original film. Later, her only surviving child is also brutally murdered.

Her son Dewey, now 50, is seen living in a trailer. He is last in possession of Tatum's ashes kept in a small, memorabilia shrine next to a framed photo of her son and ex-daughter-in-law, Gale, labelled "Tatum".

Fate
It is unknown if Mrs. Riley is still alive, as Gale nor Sidney mentions concern for her reaction after Dewey's brutal murder. If she passed away, it seems more likely Dewey would also be in possession of his mother's ashes. However, it is also possible Dewey's father is in possession of them if he is alive.

Another possibility of her death stems from the fact that Dewey may be in possession of Tatum's ashes completely, if they are not spread among family members.

Trivia

 * She is described as "a friendly, graying woman. This is Mama Riley. She wears a comforting smile" in the script.
 * Her husband is unseen, and she is known as "Mrs" indicating she is married. It is possible she is a widow, or their father is working out of town.
 * It is possible she passed away between the murder of her daughter and the murder of her son twenty-four years later.