My sister who is co- guardian with me has denied me visitation with my mother unless I followed HER rules. She and I are fighting as to whether her grown daughter can live in the house with them as she is a drug addict recovering. I have said she couldn't my sister insists she can. I'm tired.
Now if its sister's home, she can have anyone she wants to live with her and maybe able to keep u from entering her home. But asca guardian, don't think she can keep you from making sure Mom is OK and taking her out. I think you are required to keep check on Mom. This would be a question for the Court who appointed you guardian or the office you report to.
Your sister feels that she being supportive of her daughter. How is your niece doing in her recovery?