Hi Bobbi,
I can't speak much for the Drazi as I've never used their fleet; and no one in my gaming club uses them. The Centauri are a different matter however. I don't claim to be as experienced as many other on this forum, but out of 15 games with the Centauri fleet, I've lost only 2 battles. In my current campaign I'm winning with the Centauri fleet, with my hands behind my back.
A lot of the other replies are with choosing fleets, however if your friend doesn't have those ships on his roster, then he is stuck. It might be worth you posting what ships he does have; and fellow Centauri players can advise him even better.
Your original message mentioned tactics . . . well here's my opinion, for what its worth, and space combat games are something I excel at.
Firstly he needs to remember that it is continous, you have to move, or attempt to stop and risk breaking formation.
Secondly think in terms of naval combat in todays climate [well perhaps not todays!] ships need formations. Ideally you want to place your ships more than 4 inches away from each other, but obviously within 6 inches, unless they aren't a squadron. I know some people may disagree with me, but DON'T mix squadrons of ships, the more differences between ships you have the more chance you have of forgetting one ships special rules. Massed squadrons of the same ship are perfect for Centauri, and I don't care what any one else says, my success rate proves my theory is correct.
Thirdly, just moving in a straight line is not tactics, outflanking and enemy and using your speed and agility to your advantage is tactical. The Centauri have plenty of ships with good speed and agility, and a devastating close up frontal armament, the TRADITIONAL vorchan is a perfect example. Use your benefits and play to your own strengths, for instance, a slow fleet like the narn will suffer from fast and agile slashing actions from the flanks.
Fourth, use the hyperspace rules where allowed, and don't be scared of the deviation, if you make sure that you put your jump point is more than 12 inches away minus your ships crew quality, you'll be fine. If you place your strike well, i.e behind an enemy formation, by the time they have turned to face you, you will be able to fire again. If you use hyperspace try to draw out as many of your enemy ships by offering one or two TEMPTING targets [I like to use primus for this as they can take some damage.]
Now, specifically against EA, this is one of two fleets of lost to and only once. I was experimenting at the time. Use primus and ELUTARIAN bombardment destroyers to take out any long ranged missile ships he has, as soon as possible, as they will present a problem unless your ship has interceptors.
At battle level 3 or more points, your fleet should absolutely be including at least 1 primus class or tertius depending on your in service dates. Any of the raid level ships are a good choice, the sulust is my favourite, but I'm also partial to the Elutarian, and the Prefect class.
Skirmish level I'd take maximus without exception, use them as fleet defense and support, and allow your bigger ships to what they do best.
PM me if you want more advice, happy to help out a fellow fanhead.