The Path of the Righteous - S1-E11
Continuity mistake: After Fisk says we don't always get what we want, not in this world. Wesley responds that someone of us deserve to. Wesley is looking over at Fisk in this shot. It cuts to a different angle and now Wesley is looking down. (00:22:19)
Chosen answer: After some research, I can say that no, Cass is not a character of Marvel, nor is he present in the Netflix show. As far as I can tell, it's either a real person, or a random name chosen for the coffin, most likely the former. In another season of Daredevil, the show utilized a real cemetery displaying real names in the tombstones.