How old is the movie?
A group of old people living in a hotel. A man turns up and pretends to be the son of one of the lady's staying there.
1998-2005.
Mrs Palfrey at The Claremont (2005)
Think Movie Dude has spotted it. Check http://www.imdb.com/title/tt0421229/?ref_=fn_al_tt_1 to see if it strikes a memory.
It was also an earlier BBC Play for Today with Celia Johnston in the role of Mrs. Palfrey. I loved it when I first saw it and would love to see it again and wonder if any member might have a copy to swap or trade?