Faced with making some “bad” moves for the better of everyone. Being the bad guy because no one else will do what needs to be done.
example: Calling in the housing authority on my sister while she’s in the hospital so they will decertify the house and she will not be able to return. The house can them be sold which bring my mom one step closer to the nursing home. I have four weeks to decide.
What's your plan for your sister's living arrangements when she cannot return to the home she has been paying rent on? It cannot be "better for everyone" unless it's better for her too.
Be careful about involving the authorities. If the house is a rental, they may require your parents (as the owners) to make appropriate improvements in 30 days. If they condemn the house, they may require it to be torn down in 30 days or the city/county will tear it down and send the owners the bill.
I've been the bad guy - getting guardianship of my father, moving him into MC, and selling his home to finance his care - over my father's and one sibling's objection. My solution was better for _everyone_ - my father, my mother, even the sibling who objected but couldn't provide the quality care my father needed. But it wasn't easy and it doesn't get any easier.
It's difficult when you have a plan and everyone doesn't want to fall in line but before you move into the "force" part of implementing your plan, please make sure you are doing it because it really needs to be done and it will be better for everyone. You are going to create family rifts that may never heal. Make sure it's worth it.
If you mother needs to qualify for Medicaid in a facility, some will accept her before she completely qualifies if only "assets" are disqualifying and those assets are signed over to be sold by the facility management and spent down on her care. Your father and sister may accept the facility management selling the rental house better than you pushing the issue pro-actively.