WARNING: SPOILERS for Star Trek: Picard season 3, episode 3- "Seventeen Seconds"
While he's never made an actual physical appearance in Star Trek: Picard, the late Thad Riker remains a crucial story point for his grieving parents, William Riker (Jonathan Frakes) and Deanna Troi (Marina Sirtis). Thaddeus Riker was born on the USS Titan in 2381, two years after Riker took command of the ship at the end of Star Trek: Nemesis. Thad also has a younger sister, Kestra (Lulu Wilson). Thad became ill with a rare disease, prompting the Riker family to effectively retire from active Starfleet duty and relocate to the restorative planet Nepenthe. Despite their efforts, Thad succumbed to his illness as a teenager.
The Riker family remained on Nepenthe, where they provided refuge for Jean-Luc Picard (Patrick Stewart) and Lieutenant Commander Data's (Brent Spiner) android offspring Soji (Isa Briones) in Star Trek: Picard season 1. The lone appearance by Thad Riker was a photo of the infant Thad with Picard seen in the Rikers' home. While Riker and Troi were clearly happy to see Picard and were more than willing to help him on his mission, they were still clearly mourning Thad. Their grief has endured into Picard season 3, with Riker clearly affected by Picard meeting his previously concealed adult son, Jack Crusher (Ed Speleers).
Why Thad Riker Is So Important To Star Trek: Picard
Thad Riker's death was a life-altering event for both Will Riker and Deanna Troi, forever changing their worldview and priorities. Troi's one caveat about helping Picard in season 1 was that Kestra not be put in danger, as she couldn't bear losing another child. Once a career-minded officer on the fast track to the admiralty, Riker essentially gave all that up to take care of his family, which was more fragile than he had previously realized.
Clearly still quietly suffering in Star Trek: Picard season 3, and now seemingly separated from Troi, Riker implores Jean-Luc to get to know his newly discovered son as best he can in the episode "Seventeen Seconds," though Jack is reluctant to interact with Picard. In perhaps the most heated debate the pair have ever had, Picard accuses Riker of playing it safe when he assumes command of the Titan-A due to his fear of further loss. An enraged Riker orders Picard off the bridge, but deep down it's likely he knows Picard is right.
Where Is The Rest Of Riker's Family In Picard Season 3?
As Star Trek: Picard season 3 begins, Riker is a reserve officer, presumably still living on Nepenthe with his wife and daughter, though he suggests an estrangement with them in "The Next Generation." It seems likely Deanna Troi remains retired on Nepenthe taking care of Kestra, though enough time has passed since season 1 that Kestra could theoretically be away at college at this point. Neither Deanna nor Kestra has played a significant role in Picard season 3 so far, though that seems likely to change.
Deanna Troi made a brief appearance as a hologram with the newborn Thad in Star Trek: Picard season 3, episode 3's flashback. The circumstances of Deanna's full-time return are unclear; returning TNG alumni like Worf (Micheal Dorn) and Geordi La Forge (LeVar Burton) are still associated with active Starfleet assignments, so their inclusion is easier to sort. When Deanna does finally make her return in Star Trek: Picard season 3, it figures to be an emotional moment between Troi and Riker, two grieving parents trying to put the shattered pieces of their lives back together.
Star Trek: Picard Season 3 streams Thursdays on Paramount+.