As the game enforces ENY to deal with numbers imbalances by enforcing lesser capable aircraft and vehicles into opposition, no problem there, that's OK.
As there is DARBAR, aircraft and GVs are already capable of being tracked, no problem there as it works both ways, so that's OK.
As owning three accounts on the same side means that there is no cross country map information or individual player tracking, no problem there, so that's OK.
As his attention is spread over 3 accounts that's 33.3r% attention per account meaning he is much more vulnerable over other players - he is personally disadvantaged especially on bomber runs, there is no problem there, so that's OK.
There's no cheating present in what you are bringing forward, or added advantage. If you use the games tools while he goes on a strat run, there are 9 kills in waiting.. Looks to me like you have misidentified the issue.