Kaido doesn't have to know it. It's the manner in which he dies that's important. Dying in a huge war that is supposed to Eclipse Marineford would suffice, as opposed to dying on some unknown Island in an unknown manner. Much like how nobody remembers Xebec or the Island he died at. Dying here on Wano is enough to cement Kaido's name into history for him to never be forgotten. It's not a matter of what Kaido thinks but rather how the World will remember this war, and that is, how the Borders of the Country of Wano was finally opened up due to the downfall of Kaido. If he's killed here, this will be the battle he is most remembered for, and where he met his demise.
Of course, we know that they won't just be some brats, but they will be the next great pirates.
Which is why I keep reiterating the point that the important perspective here is Kaido's.