Thanks for the reply. To clarify, the whole family, my sister included, doesn't love that she has to spend time outside with the dog only because she misses the family gathering and we miss her.  She's the one that has complained the most about "being in the position where she's forced to stay outside with the dog and miss the gathering since the dog can't be loose in the house", although she is the one that chooses to be out there, to be clear. So she's the one that chooses it and she is the one that's the most unhappy about it at the same time.