Roommate is partially blind. She always want me to make sure her dog pee's. I told her daily to keep back door open so my dog can go pee.?

I went on vacation leaving my dog with my daughter. My roommate has his sister staying with him, that I help with her with meals a heath care provider which doesn't include taking the dog out to pee. My daughter had to leave to work early 4:30 am one time, which is dark at that time. My dog an inside dog has a mind of it's own goes pee only if she feel like it on the day my roommate sister Nancy took her dog out to pee at 8:00 am. daylight. I have told Nancy to leave the back door open for my dog so she can go pee when she is ready. She always wants me to make sure that her dog pee, that day Nancy was suppose to leave the back door open as I always told her to keep it open daily, on that day my daughter lock the back door. Nancy which is 59 was confused didn't know if my dog went out to pee or not, now remember she always wants to make sure that her dog pee's, now my dog she wasn't sure, so she left the door lock and closed, it was until 12;00 p.m when I got back from vacation, lucky I did, the back door was closed, She usually wakes up at 12:00 - 1:00 my dog would be holding the pee all that time. My dog usually barks downstair at the back door, but whose to say that she could hear that.I do believe an eye for an eye. these are adult dogs, What should I do? I believe she only cares about her dog and not mine. The dog belongs to her brother and me.thx