Agree that this is probably the best bet in the Triangle based on what the OP said, based on location, quality of hotel, etc. It will never be mistaken for the Mardavall or the Blue Palace in terms of sheer luxury, but it's comfortable enough.

Downtown Raleigh is still a couple of years away from being a true "destination" in the sense of what, say, Charlotte, has done to it's down(Up)town area, but I think it will get there. But there are some good dining/entertainment options that are very close to the Sheraton Raleigh.

Hope the OP's relatives enjoy their stay here!