All good, I had to reread the last chapter several times just to make sense of it, since it was so strange, lol. I wrote a more detailed explanation here if you're curious: https://myanimelist.net/forum/?topicid=1405787 bottom post. Cheers.
C'mon
If there ever was a series were the siblings magically aren't related is this one
I mean, how can Hikaru be the biological son of those 2 giants lol