Hannah - I would look into getting them moved - it won't be easy, but in my recent experience with my Mum, if your gut feeling is that something isn't right, then its most probably not.
My Mum's feel always looked swollen when she was in her first Care Home, and all they kept saying to me, was that because she walked up and down a lot, this was the cause. When I moved her to her last Home, the swollen feet disappeared, because she was getting much better care.
If the staff have common courtesy they would offer your Mum a cup of tea/coffee.