I hope your DHs Union is successful -
As per another thread on here about snow days, ACAS states that
There is no automatic legal right for a worker to be paid for working time they have missed because of travel disruption or bad weather.
If employer-provided transport is cancelled because of bad weather or travel disruption, and a worker was otherwise ready, willing and available to work, the worker should be paid for any working time they have missed.
It goes on to say only if the employer decides to close their premises altogether that the employee is entitled to be paid, which wasn't the case for your DHs employer it would appear.
I expect your DHs boss saying he needed to turn up to be paid was because of the "ready, willing, and able" part of the guidance, but it was a moot point whenyour DH tried his utmost to dig himself out of the snow, but still was not able to present himself. It would seem like the decent thing to do to recognise his best efforts, so hopefully the boss will be "encouraged" by the Union to do so.
Losing a day's pay is harsh when conditions are so extreme. But to my mind, if it's a question of risking one's job for the sake of taking a day's leave, then I'd opt for that.