What you described is not a conflict of interest. His representation of MS was not compromised by his being on the board, and vice versa.
The company I work for (and probably most in the nation) would fire an employee for having less of a conflict than this.
Please give a scenario (not necessarily related to the Schiavo case) that best defines 'conflict of interest' in your view. At this point, it seems that your view of it is different from the norm.