Elias Stilinski is the Sheriff's father who resides at Goodwater Assisted Living facility due to dementia. Beforehand, he was an army engineer who had a poor relationship with his son.
Like his grandson, his nickname was also "Stiles."
In Sundowning, Scott, Lydia, and Malia visit him in order find someone named "Stiles." After the Sheriff forces them out of his room, Elias taunts him to crawl back to his dead wife and loser son before becoming confused again.
He is played by Patrick Gorman.