It depends on the situation -- but all of my family on both sides also understands that it's NOT an open-ended ticket. If you need a couch to crash on for a couple of days while making other arrangements, you're welcome in our home. No one is going to move in permanently...we have our immediate family unit, and keeping it running smoothly is the priority in our home. My cousin has stayed with us for as much as two weeks before, but he made sure to only come back to sleep, cleaned up after himself, brought in his own food, and went to great lengths to be unobtrusive. That said, if mother-in-law had health issues that required supervision -- I'd gladly help her find a house or apartment nearby where we could check on her.