Colby needs to go back and challenge the requirement with his boss. Business isn't entirely a top-down process -- if it's not a good idea, it's his duty as an employee to express this. Lots of great ideas and insights come from the most junior people. It's easy to come off as difficult when voicing dissent, so it's important to be thoughtful and constructive.
In this case, it's easy -- just bring Microsoft's own data to the table. According to http://www.ie6countdown.com, only 2% of the US uses IE6, and it's clearly not 2% more work. In addition, big sites like Facebook and YouTube have abandoned IE6 support. The company's needs will differ from the averages, but it's a good starting point to start looking at the data.
In this case, it's easy -- just bring Microsoft's own data to the table. According to http://www.ie6countdown.com, only 2% of the US uses IE6, and it's clearly not 2% more work. In addition, big sites like Facebook and YouTube have abandoned IE6 support. The company's needs will differ from the averages, but it's a good starting point to start looking at the data.