Here’s some apparently good info on Apache’s specifically, mostly down near the very bottom …
www.deej.com.au/rlapache.htm
The indication is the second crewmember is called a “copilot/gunner”. That person could fly the helo in a pinch, but would be hard pressed to do so & also fight the aircraft. Meanwhile, the pilot (in the back seat), doesn’t really have any input to the weapons beyond point & shoot.
Here’s what I do know about though … The corresponding concepts in USN & USAF aircraft.
In USAF two-crew attack aircraft, e.g. F-4, F-111, F-15E, there is one pilot & one “Weapons Systems Operator” The WSO is not a rated pilot, but rather a navigator. He (or she now) has a small amount of flying skill & training, but probably could not sucessfully fly the airplane through a normal flight, much less execute a mission. The WSO’s cockpit however, is equipped with throttles, control stick, rudder pedals & a complete, if miniature, set of flight instruments. So it’s completely possible to fly the aircraft from the WSO’s (aft) cockpit, provided the occupant knows how.
In the USN, in the A-3, A-5, A-6, F-4, F-14, etc., the second crewperson is also not a pilot, but the USN equivalent of the USAF navigator, called a “Naval Flight Officer”.
The BIG difference is that the USN aircraft do NOT have any flight controls in the NFO cockpit. No stick, no throttles, no rudder pedals. (S)He is 100% along for the ride. It’s 100% impossible for the back-seater to do anything beyond control the weapons and eject. Due to the side-by-side seating of the A-6, the NFO can strain to reach the pilot’s stick, but not throttles or pedals. So (s)he could manuever the aircraft a little bit, but not really control it very well or for very long. Without a functioning pilot, it’s time to jump out.
There are lots of advantages to leaving the flight controls out of the weapons operator’s cockpit. It sems teh AH-64 at least, has at least rudimentary flight controls for the copilot/gunner.