I finished reading this manga a long time ago. But I just read the last chapter. So I don't have the answer to all of them, but here goes:
1. Yes. Katou the Butler is the father of Youya.
2. This manga had an open ending. So really its up to you to interpret the last moments of this manga. But personally I think he didnt die because he had just decided to live again and i would like to think that new will to live again would mean he made it.
By the way, at the last page sensei did say that she left he ending unclear for us to interpret it. http://www.mangago.me/read-manga/sakura_gari/an/sakura-gari-chapter-9.html/90/
3. sorry i don't remember enough to answer that one.
4. In a simple way Souma let go of Masataka because he loved him. In my opinion, I think it was because he feared that he would not be able to let him go the more he stayed with him. Masataka had his dream to be a teacher and do something in his life. But really Souma only had Masataka. Maybe in a sense it was that Souma wanted to let go of him before it got to the point that he might hurt Masataka again.
5. This is like number 2. Its for you to decide. For me though, I feel that it was the last time they saw each other for that lifetime.
Hope that helped. :)
Oww Thank you so much Yuuhi(⌒▽⌒)
You're welcome ('◡')
4. I would say that it also may be because Souma was ready to go to the police to come clean about what he and the others had done in that family. That being the case, it would be fitting that he would want to spare Masataka of any involvement. Especially since he wasn't sure if he would even make it back from that.
Thank you IOTR(⌒▽⌒)
This is my first time read this manga and I read it in one go.Maybe cuz it's full with sadness not to mention full of blood,I still confused 'bout something,and here they are:
1.Is katou youya's father?
2.Is Souma still alive?
3.Did every servant slept with the young Souma back then?
4.Why did Souma chased Masataka away?
5.Could they be together again?
I'm so sorry with these silly questions,but if someone kindly enough to answer these,you'll make mind light again,by the way it's 3am here and I'm dead curious.So sorry with my messed up grammars.