If he hasn't seen the game don't confuse him. It is very different from AH ...or from any other game for that matter.
Let me give you a brief description of the game.
It is a game where you can play as either a fighter or bomber pilot, an infantryman, a tank/scout car/truck driver , a navy ship (destroyer or transport or PT boat), an artillery piece (or triple-a gun) or as a commanding officer (strategic play via map).
The game itself takes place in a persistent world server. There are no 'zones'. Meaning yes, there are an average of about 3000 people online playing the game at any given hour.
The map of the game is set in a map of europe with towns and airfields and naval yards connected by roads. In between these towns/airfields/naval yards there are Firebases.
The objective of the game is to capture the towns and airfields and naval yards of the opposing side. The map is moved by one side gaining control of the firebase and then launching attacking forces from that firebase onto the opposing town.
Each side has its armed forces split into divisions which are in turn split into several brigades each. These brigades are either armor brigades or infantry brigades (navy and air force are separate from land army but they have their own brigades). There is also a paratroop division with its own brigades (that can only be placed on airfields).
The way the game is played starts when players who are High Command (strategic play) move or order brigades or divisions onto towns and order them to attack or defend a place. High Command also manages supply (by resting a unit in a rear town or sending brigades to resupply towns where the division HQ is located).
When the orders are set in the strategic map by High Command players.. either attack or defend order, the town or objective becomes an AO (attack objective) and the town flashes on the map for all other players to see. When the enemy High Command places an AO on your town, that town automatically flashes a different color and automatically receives a Defense Order (DO)
There can only be a limited amount of AO's active at any given time. I've seen a max of 6 AO's on place per side (meaning 12 towns total can be involved in combat at any given time)
The AO / DO's focus players into playing on a certain front/town battle. Only towns with an AO on it can be captured. Towns with DO's alert players that the enemy is coming.
The battlefield can be very fluid. Since players on both sides are focused on these AO towns you get a huge variance in the coming battle. Sometimes the enemy will mass armor and assault the town in a heavy mechanized push...sometimes they will use a lot of infantry to infiltrate the area (especially at night!)... sometimes you will see an insane amount of bombers plastering the town... sometimes all of this at once.
The tactics of the players and the high command as well as that of the field officers (those directing the attack or defense in combat not from the map) coupled with the supply situation and bridage/division placement is what determines if a town gets captured or not.
Supply is the key to the game now. Before the AO's were introduced each side had an almost unlimited supply of units so the fighting was one of who attritted each other's patience the most or which side had the most players online to rush-bump the defenders out of the town. With supply in place and AO's in place, it becomes a matter of taking and holding positions in a town and destroying high value units of the other side (tanks mostly) and claiming victory before the other side can bring in another brigade with fresh supply to throw at you and overwhelm you.
Many old players didnt like the AO system (and truly, when it was first added it WAS a mess but it got tinkered and smoothed out, now it really works) because it limited their ability to choose where and when to fight. Before the AO system players would just ninja-rush empty towns, with some 5 man squads taking whole cities in 20 minutes which was rather ridiculous. Now, both sides must fight through the other's forces to win.
The game is not perfect. It has its good and bad things.
The good:
Nowhere else.. no other game will you see bigger battles of combined arms. Infantry and armor and air power all engaged at the same time.
The bad:
Graphics are out-dated. This is the biggest complaint of many people. Personally I dont mind them... I prefer solid gameplay over flashy graphics with poor gameplay. WW2OL has very solid gameplay.
Flight engine is arcadish. Dont expect an AH type fight in WW2OL air. At best its more like the old MS combat flight simulator on easy mode. Their flight engine also has a very crappy G-force effect system.. sometimes just pushing your nose up a bit with the G indicator showing just 2g's will black you out or lock all your controls (even when you flying slow). Aside from the crappy flight engine the flight itself has one neat thing: it does give you a 'feel' of flying because the cockpit is 100% 3D. Your head bobs as the plane turns which is a really nifty effect.
Finally, something that is good and bad about the game at the same time: Steep learning curve.
For many coming new to the game they get VERY frustrated because the game itself is very unforgiving. Most new players start with a rifleman or a light tank..head out of the army base in the middle of a battle and get killed in less than a minute with no clue who killed them, from where or WHAT killed them.
Worse yet, since the game itself is highly realistic when it comes to ballistics and armor stuff (which makes tank warfare so cool in this game!).. many players, especially new players, think the game is broken or that it sucks because they emptied their 100 round so anti-tank ammo from their anti-tank gun or from their own tank into an enemy tank and it didnt die..and the enemy tank turned around and shot them dead in 1 shot.
... and they dont realize they were using a light tank that carried a light anti-tank gun (2lbr) against a heavy tank (Tiger) shooting it in the front armor (where there is no chance in hell it would ever penetrate) from medium to long range (where the light AT gun really has no hope to even scratch the paint).
.. or that they were running in the open field with their rifleman and got shot and killed out of nowhere... by the enemy infantry machine gunner concealed in a treeline 400yds away.
.. or that they fired 20 rounds of artillery anti-tank at enemy forces from the hill they were in over a period of 10 minutes and then all they heard was a BANG and they were dead. Turns out their constant shooting gave away their position and the enemy marked them and vectored a dive bomber to take him out... but the player never figures this out.
All in all, the game is very fun to play even with outdated graphics. For flight stuff stay in AH, for ground combat go to WW2OL