Those are difficult questions to answer because residents’ rights in assisted living facilities are governed by contract and by state regulation, not by federal law, so the answers can differ from state to state and from facility to facility.
Start by looking at your sister’s contract with the assisted living facility and see if it answers these questions. If not, or even if it does and you want to make sure it’s in compliance with state law, take a look at your state’s assisted living regulations.
Another place to look is the National Center for Assisted Living, which conducts an annual regulatory review and summarizes the rules in every state, plus the District of Columbia. You can check out their 2019 report with state-by-state summaries here.