Two stars. Rated PG-13. 117 minutes. “Breathe” is meant, no doubt, as a sincere homage to the late disability advocate Robin Cavendish, who died, after living with polio for 36 years, in 1994. Commissioned by his son, producer Jonathan Cavendish — who plays a minor role in the film — and directed by Jonathan Cavendish’s business partner, actor Andy Serkis, the movie has the tone of a eulogy delivered by a dutiful son: affectionate, complimentary and maudlin.