Your mom agreed to watch the dog and care for the dogs in their home for these people. Dog sitting at a residence means you agree to go to the house to get the dog to let it outside, you have to get it food and water, exercise the of and keep it company for a while. While you are there you would notice if things like water pipes broken or if the house had been broken into, if electricity was off , any problems that may arise.
Your mom is also responsible for notifying the owner if anything happens to the dog. Taking it out of the house everybody in the neighborhood knows that nobody is home because the dog hasn’t been out, not the normal routine besides the car being gone and no lights being turned in or off. They don’t see anybody coming and going and the house is basically abandoned, free for someone to break in and either vandalize the place for fun like youths might do or steal things from the house.
Of all the years I have done dog sitting for people with her gone on vacation or emergencies and they request me to take care of their animals at their house I have always made sure that things are brought in, no papers or trash or left around, mail, branches from high winds etc. With your mom breaking the contract with these people that she doesn’t know she was leaving the house open for anything to happen to it and is taking on the responsibility for it as well as taking the responsibility for the dog getting in your house or outside if it gets free. if the dog gets hit or killed your on could get sued and be responsible for all medical bills plus possibly the cost of replacing the dog should it die,
Do you know honesty if your mom had hired somebody to watch the cats and the dog at your house and they decided to take it upon themselves to bring them home and say one of the cats was killed or your dog was killed would hundred or maybe even $1000 replace your beloved pet being dead? Would that be sufficient to replace all the memories and make you love a different animal just as much? Mention this to your mother and have her rethink her idea of bringing the dog to your home, her hearts was in the right place she wasn’t thinking about the ramifications of nobody being home for a week, nobody going in and out of the house or watching the place.
Your mom took on both responsibility and liability for any damages that occur to dog as well as the house while nobody’s there, especially if somebody breaks in in vandalizes the place. She wouldn’t have a clue what day, morning or evening and on which day, same for any fire or broken pipes, overflowed toilet etc. that’s also another reason people to have their pets watched in their home besides the obvious comfort for their pet.
Other than saying something to mom about the responsibility of removing the dog off the property, and the owners not being happy about that, They will be even less happy to know their dog was miserable at your house, fighting and having spats with your pets as well, one scratch may be missed but not if it’s the eye or lots of fur is missing, an ear gets bitten off eat, things like that won’t be missed nor excused and she may even be sued for breaking their contract.
Other than pointing out the risks etc about not checking the house, not having the dog at home where it’s most comfortable and not keeping her word about what she had agreed to do, she’s also taking the responsibility for the visiting dogs health and stressing out not being home, no owners around and on alert. Having two female dogs in the same hose is never a good idea as they usually fight and get very territorial over things.
Besides bring the dog home I hope she was smart enough to bring the dogs dish, bed and food with. A sudden change in diet can stress a dog, cause it gastric upset, diarrhea and vomiting.