trying to apply family titles like aunt and nephew and cousin etc to the et'Ada is kinda funny because if you do that then-
1: Akatosh killed his own brother or definitely helped with having his other brother (Trinimac) do it in what was probably the greatest war comprising only family members in the history of ever
(technically a freebie but shush) 2: either had another kid (the LDB) or hired a mercenary to fucking beat the shit out of his oldest son for either being a prick (eating the world), or getting into his dad's weed stash (trying to rise the dragon cult again which means he will be worshipped and not Aka), or a secret third thing
3: if you accept that Mehrunes Dagon was made by the Magna-Ge and accept that at least the majority of them were offsprings of Magnus (who would be Akatosh's brother) then his grandnephew tried to break into his house and he reacted by understandibly violently beating him and throwing him out the window while the other Aedra... idk... watched? And even if you only have him as Akatosh's sibling the above point still stands
EDIT because I forgot the plot of ESO: Molag Bal is trying to take his late brother's house/art project/evil ass torture building/good ass love and hope building only to get into conflict with his niece (Meridia - who will also later get into conflict with Akatosh through the Torture Elves vs Insane Guy moment)
like it is still the wills of gods but it is also just the pettiest and largest family in history and you just have to deal with their bullshit