Several children points to gene sharing.
...had 3 children.
Someone had 3 children, possibly one of the other siblings. It wouldn't be the first time someone took ownership of a child that wasn't theirs.
So all of her children are fake?
They may not be her children and no, they're not "fake" - they might just be someone else's.
For example, Jack Nicholson grew up believing he had a sister only to have researchers uncover the truth (when he was 37 years old) that his sister was actually his mother and that his father was still alive.
https://www.unilad.com/celebrity/news/jack-nicholson-discovered-sister-mom-330003-20250718
You really are deep into the conspiracy stuff.