As a regular public speaker, I would be delighted to compose your boss's best man speech. However, in order to do that I would need material from him about the happy couple. I would also need to know what sort of speech he wants to give -- funny, best mate or more serious, paternal are just two styles I can think of.
My background is as a copy editor / book person. So I have the skills necessary. I look forward to working for you and your boss.
Regards,
Stilman Davis