The last episode of This Is Us featured a powerful scene between Randall, William, and Jack, who was not seen but definitely felt. On their road trip to Memphis, Randall and William (Randall's biological father) stop at the site where Jack's ashes have been scattered. William pays his respects to Jack, who adopted Randall and raised him as his own.
On one level, this affecting scene drives the narrative: Both of Randall's fathers are finally meeting. It also serves as a reminder that we can feel — and speak to — those we've lost. Talking about death and grief can be difficult (though there are strategies to make it easier), so ceremonious actions like these can help. Scattering ashes in a meaningful location is one way to see your loved ones off, but there are plenty of other ways to lay them to rest if they've been cremated.