Yeah my take is if he's collecting a pension from the service he should still be held to account and any punishment be taken out of his pension somehow.
Regarding not being able to do anything, well I can see how it is internal stuff so not much that can be done but there is still this:
$1:
using police surveillance equipment to spy on an alleged former lover.
They can at least charge him with some type of stalking law. at least the creep will get a parting gift of a criminal charge, even if a lame one. Should be a slam dunk if they knew he used the equipment and who he was watching.