Max Dugan Returns (1983)

Here's a perfect but little-known film for a grey day. Marsha Mason is the widow living very simply with her teenaged son (Matthew Broderick in his first screen role.)  Out of the blue her father whom she has not seen since she was a child appears, on the run from the mob with a suitcase full of bucks and only a few months to live.  He is played by the unflappable Jason Robards Jr. and wants to get to know his grandson and spoil them both.  He procedes to spend like a drunken sailor and Mason has trouble explaining all the new acquisitions to her son, her nosey neighbours, and her cop-boyfriend (Donald Sutherland), especially when Robards turns their humble home into a mini-palace. It's a feel-good movie with an ideal cast, but helped most of all by Robards' cheekiness.