Leah's first born Ruben is sleeping with Rachel's handmaid Bilah who bore Jacob Reuben's brothers Dan and Naphtali. This is like sleeping with his stepmother, a woman that his dad has already slept with. Not good at all. The incident is noted here but, the consequence not fully discussed.
Sometimes the story line moves on without you even before your death. Less frequently to that, it may even come back to you for a final mention. Isaac was a great enough patriarch to have had both. How he had spent this time was no doubt important for himself, hopeful peacefully and content and richly blessed, important to those closest to him. God's written record allows him that privacy yet pays him the respect at his end.