Try the following as your batch file:
Make sure the last line in your .cmd files is EXIT
start /b "" "c:\util\Game controllers - Enable.cmd"
start /wait "" "P:\Program Files (x86)\Lockheed Martin\Prepar3D v2\Prepar3D.exe"
start /b "" "c:\util\Game controllers - Disable.cmd"
Prefaced 1st & 3rd line with start /b so that all 3 commands are called from the same parent and you can see them launch to confirm. The double quotes on each line are a kludge of sorts to get around the window title parameter and be able to use long filenames/paths.