You should inform him that this would be a "Bad Thing."
Ther term "Lightening Arrestor" is a serious misnomer: until you get into (lightning protection) systems costing thousands / tens-of-thousands of dollars, you can pretty much plan on any lightning strike taking out the data center if you connect to anything on the roof with copper.
The best protection you can provide is to isolate the stuff on the roof with fiber and protected / isolated power.
Even when properly implemented (fairly rare), "gas poppers" and the like are only good for "near hits" and bleeding off static buildup.
If you are interested in seeing some real lightning protection stuff, check out PolyPhaser. They provide consulting and product that protect commercial radio towers and other structures. I'm sure there are other providers, but my experience with PolyPhaser to date has been very good.
Good Luck
Scott