The way it was phrased by the admin on the official Missing Mother facebook page, it said
"I spoke with her a couple of times that morning. Going out for dinner was in the plan. We know she had picked up a few things at Safeway.
and
"She was going out to dinner with her fiance and daughter. She didn't say where."
I guess "going out to dinner" could mean anything - a restaurant, his family's house, a friend's house. I have always lived in very touristy/vacation-y cities, so restaurants open on Thanksgiving is more of a norm to me, but I am guessing in a smaller town it may not be as common.