Sometime in 2996 3A, Eréstor was present when his daughter gave birth to an unnamed Atani son. Eréstor started to care for his grandson after his daughter became mortal.
On October 25, 3001 3A, Eréstor attended the Council of Elrond in discussion of destroying the One Ring. He believed that the the Wizard Tom Bombadil could be called upon to help, or whether the Ring could be sent to him for safe-keeping, but that option was rejected.
After the War of the Ring ended with Sauron's defeat and the destruction of the One Ring, Eréstor was among the party that accompanied Arwen to Minas Tirith for her wedding to Aragorn. They arrived in the city on Midsummer's Eve.
At the beginning of the Fourth Age, Eréstor was among those that stayed in Rivendell after Lord Elrond travelled to the Undying Lands and left his son Elladan as the new lord while Elrohir became the first Lord of Tolfalas. Eréstor was respectfully loyal to Elladan and held hope that Elrond would one day return to Middle-earth in the future.