Why does social worker at nursing home keep trying to convince me I can't get guardianship?

I should be able to seek this without her input. I have some concern that my mother will try to go home even though she is completely unable to physically take care of herself. And in my opinion has some mental short coming after this stroke she suffered. But the social worker just seems to avoid my request for letters from treating doctors as to my mother's mental capacity. Why would it matter to her if I want to know this and or I try to get guardianship, I already have medical and financial POA, and I have been named in her will to get everything. The thing is my mother has nothing to leave upon death but her homestead and Medicaid will take the homestead when she dies. So, it should be clear that I don't have anything to gain of value, I only want to ensure that she is not allowed to go home when she is not able to take care of herself. The social worker also keeps telling me that I can't enforce the POA's unless mother is can't make decisions, the social worker states she can based on BIMS scores which I feel is not a true test of her mental capacity. I feel like they are concerned I will find out something that differs from their assessments.