Jonas's grandmother lives alone in her apartment where nothing has changed for decades. She's kind and proud of her grandson, and she bakes the most delicious sticky sweetroll.
During your escape from Vault 101 you can find a file on the Overseer's computer which states that Anne Palmer, her daughter, was team leader of a scouting party that left the Vault to explore the outside world in February 2241.
Palmer is old enough to have retired from work duty in the Vault, and therefore no longer has a Pip-Boy.
Trouble on the Homefront: She will be holed up in the classroom with Amata's rebel faction. She explains that during your escape from in Vault, her grandson Jonas died in suspicious circumstances which she attributes to the Overseer.