I take it you enjoyed Snake Eater?
Sounds like he wants a Trauma Centre mini-game in his BF3. While it might be "cool" to patch up your team mates once or twice, they're going to be constantly shot at, which means you'll spend more time dragging and patching up than you would actually playing the game proper.
Either that or you would only do the Trauma Centre stuff at scripted points which would make the game feel "staged" and "linear" and all that jazz.
The single player is going to feel CoDish. No getting away from that really. There will be way-points, you will have to do everything, occasionally you'll possess the pilot of some vehicles (though you'll probably get to actually use the vehicle yourself, rather than doing a rail shooter thing) and it will all be very "Cinematic".
This game is being built around the Multiplayer experience, which, when I saw it a few months back, was already incredible.