Welcome to the forums!
Even though you haven't seen your budgie drink up until today, that doesn't mean he hasn't had any water. Budgies, especially new ones can be very sneaky and will take a couple of short, quick sips when we aren't looking.
Because budgies take little water on a daily basis and unless they use the water container to take a bath, we won't notice a difference on the water consumption levels.
As to the mineral block and cuttlefish bone, when his body is in need of the calcium and minerals, he will make use of them.
From the photos, I'm noticing is a little staining on the feathers above the cere area. Have you noticed any sneezing and if so was the cere wet in the process?
Also the feet seem to have some crusted spots, this could be the start of leg mites.
Since your budgie is new it would be good to have him seen by an avian vet specialist, so that he is properly examined, diagnosed and if need be treated.
Best of luck with everything!