I'm not familiar with that particular'sis vs bro mom died in real life story'. It might be a very personal account within a family. Maybe it involves how the sister and brother coped with the loss of their mother, and how it affected their relationship. But without further information, it's impossible to tell the whole story.
I'm sorry, I don't know the specific 'Sis vs Bro mom died in real life story'. There could be many such personal and tragic stories out there, but without more details it's hard to share the exact one.
Unfortunately, without more context about this'sis vs bro mom died in real life story', it's difficult to share it. It could be a story full of grief, with the sister and brother having to deal with not only the emotional pain of losing their mother but also potential changes in their family dynamics, financial situations, and their own personal growth in the face of such a huge loss. But again, this is all speculation without the real story.