After helping create and run the gigantic factory/laboratory Tales From The Loop is based on, his health is declining.
SPOILERS here: Throughout the episode, we see Jonathan Pryce’s character Russ in the final phase of his life.
Nowhere is that better felt than in one of the three episodes available to critics at the time of these interviews, an entry entitled “Echo Sphere.”
But before it’s too late, he shows his grandson the titular location: an old metallic sphere that, once you yell into it, measures how much longer you’ve got to live. It doesn’t give an exact measurement, but it echoes with enough repetitions to signal the visitor’s remaining life span.