The domain name really does not help that much. If you have one domain and build up a good link profile you will rank for all those terms. He is trying to get links to a bunch of sites you only have to get them for one. Buying up a bunch of domains so you can rank for different keywords is a waste of time you can do it better with one domain with good content and good link building. What he is doing is a sign that he is not a very good SEO. That is an amateur move. Should not be hard to beat.