Dear Rapunzele,
What a terrible story! I am so sorry.
These things shouldn't happen, but sadly they do.
Of course you wish that you had been there to take care of your brother, but you did not know what had happened. When these tragedies happen you always think what you could have done different, but we just have to do our best knowing what we know at the time.
Good luck to you and my deepest sympathy for your loss.
CS