User blog comment:Kunoichi101/Chapter 964: A Time Traveling Kunoichi/@comment-25654036-20191130083922/@comment-27973430-20191130131420

I didn't interpret Whitebeard calling Oden his little brother as a sign of respect, Oden is 15 years younger than him more or less so I saw it as saying Oden is too old to be his son and since they are family now that really only leaves brother to call him.