I don’t know the specifics of his department (and am also not checking the latest policy in my department) …… but when on strike you are not working, and he and/or his line management mark him as absent on strike
He therefore loses one days pay from salary
Leave is not deducted - if on leave then he’s not on strike
Equally FWH should not be deducted - if flexi hours are taken from his balance then he’s not on strike
On Tuesday if he had 5 hours up then on Thursday he should remain 5 hours up
As he did not work on Wednesday an automated flexi system would deduct Wednesday, but a credit ‘on strike’ entry would be required
There could be a policy to deduct flexi rather than salary, but that would mean handling everyone differently depending on personal circumstances
(What about standard hours workers, or flexi workers in debt of time ?)
The department should have policy documents already on flexi rules and strike action, and also ought to have recently published how to handle strike action
I’m half inclined to think that line management have not understood/have not followed policy