Naufragio (1978)

One woman (Murguía) lives waiting for his son (Alonso) who is a sailor. She hasn't seen him for years although he writes to her a lot. The woman shares the letters and her grief with a co-worker and friend (Rojo). This last woman begins to idealize her friend's son. One day, the mother gets sick and falls into a coma. Her son arrives but she is unconscious. He has a brief but passionate affair with her mother's friend and then disappears, as quickly as he came back from the sea.

Imdb