Rudy while based on real life has also elements of fiction in the movie. One of the biggest tear jerking punchlines where all the players put their jerseys down in order to get Rudy to play is one of these fictional moments. It was indeed coach Devine who suggested and wanted Rudy on the field. Before you subscribe to symbolism in movies you should really look at the character itself and if the whole story is actually true in its entirety.
BTW Ruettiger was investigated for investment fraud by the SEC just a few years back. The charges were dropped because he agreed to pay full restitution. Because after all it was just a 'misunderstanding'. Great symbolism, the American way. Screw that global disability act. We are modeling our symbolism and our greatness based on movies who are fully or partially fictional.