You can't disable that completely, which makes sense cause else you might end up with hundreds or thousands of dead bodies on the map which you probably never will see again.
But you can adjust the time and distance when this happens. For this you need to edit the "dac_config_creator.sqf" file and look for this line:
if(isNil "DAC_Delete_Value") then {DAC_Delete_Value= [[120,150],[140,150],300]};
You can either change the parameters so the units are only removed after a given time, or distance. Or like in the default setting, first after time and then distance. This is from the included DAC documentation:
DAC_Delete_Value = [[120,150],[140,150],300]
This array defines the removal of dead units and destroyed vehicles. You can either use only one paramter
or combine both: [60,0] = only time is checked, [0,200] = only distance is checked, [30,150] = time first, then distance
1. Time (in sec.) + minimum distance to all player units before dead units get deleted
2. Time (in sec.) + minimum distance to all player units before destroyed vehicles get deleted
3. Time in seconds, until an empty vehicle without a membership is destroyed (so that it can be deleted later)