If my mother lives in my home can I dictate terms of visiting for a sibling?

When you say your sister has been behaving irrationally towards you, is it just the coming and going without your by-your-leave, or do you have other concerns about what she might be getting up to during her unannounced and unattended visits to your mother?

I assume you've tried asking your sister to have the courtesy to call before she turns up, have you?

The thing is, you do have a difficulty. Your husband and you are the homeowners, but your home is your mother's home. That's where she lives, she has no other place of abode. If you restrict visits made to her, you are restricting her right to see whom she likes when she likes. And as she's competent - frail but not vulnerable? - you're on dodgy ground there.

All the same. A normally civilised human being would understand that she can't just breeze into somebody's else's home without being a proper pest. So - what has your sister got to say for herself? And does your mother express any opinion?

Well captain you should of vanished to the other end of your house when the mouse came to visit. Your mouse deserves to eat his peanut butter in privacy.

unless you suspect shady activity i think you should vanish to the other end of the house when visitors come . people deserve to visit and they deserve privacy .
and it sounds like the mouse in my kitchen just got brains squirted out his eyeballs . hes stole my peanut butter bait three times today . maybe he was collecting it for when he became TOAST .,.
sucker !!

No one has a right to take over your home. Your mother and her visitors are guests in your home subject to your rules. If anyone takes advantage or abuses the situation you could go as far as restricting their activity, banning them or even taking legal action with a restraining order. There are options.

Your house, your rules, your right to privacy. Put up a nanny cam and have ADT make sure she is safe when you are not home.

Within some families they have an "open door" policy where siblings, nieces and nephews pop in at any time. And some families prefer to have notice that someone is coming over.

The way I look at it "your house, your rules" just as long as it doesn't result in your sister not coming over at all to visit with her Mom.

And if your Mom is frail, chances are she wouldn't be left home alone anyway.