One sister lives in apt, is charging rent for another soy.without permission from other siblings and pocketing money is this theft of inheritance

Please explain this in more detail. How does it affect an inheritance?

Any question on law needs to include your general locale as laws vary by area.

Some more details are needed here. Who owns the apartment? On what conditions is the sister renting it? What do the siblings have to do with things?

"is charging rent for another soy"

What is a soy?

"is charging rent for another soy"

What is a soy?
I think it means "son." (Y and N are near each other when texting, especially if you are walking and texting.)