Is like computer the cause

My friend has a 2000 Honda Accord EX V6.
The car will sometimes stall out after it has
been driven for a while. The check engine
light had been on and the codes read misfires
on every cylinder. After replaceing the spark
plugs and Ignition Coils the check engine
light went off the stalling problem continued.
Since then the light has since came back on
after weeks and now says there are misfires
on all 6 cylinders and also EVAP Control
System Leakage and according to Auto
Zone's print out it says most likely solution is
to replace EGR valve and clean all EGR ports.
My friend knows a mechanic from there past
and Im not a gearhead or anything but the
mechanic she knows said the problem is the
ECU computer without ever looking at the car.
So I guess my question is for other opinions
on the subject from people who know more
than I do about weather that guy would be
right most likely or is it more likely that the
issue is less complicated and more like what
the auto zone computer said because I am
trying to help this friend out but we are both
poor so any suggestions would help