An inexperienced teacher not open to suggestion

I have been working in the district for 20+ years. I don't consider myself out of touch because I'm willing to make a change however, the person I work with in a SPED class reacts to the bad behavior instead of teaching the class. In other words he don't know how to deal with a disruptive student who's hindering others from getting educated. This is driving me nuts because I can't assist him when he's constantly disrupting his lessons to deal with the student. I have tried to take the student aside but he still makes negative comments to the student after I have calmed him down. Help!