Hi Jackie,
A bit late to reply, perhaps, but your husband's severe headache was highly likely to have been Solpadeine withdrawal.
Stopping the tablets suddenly leads to rapid codeine and caffeine withdrawal.
Caffeine withdrawal, in particular, is famous for causing severe headaches and/or migraines. These do pass but it takes a few days and minor 'aftershock' headaches can last up to a week or two.
Same if he stopped drinking coffee suddenly. I have little doubt that favouring water over coffee for those few days contributed to the pain because he accidentally threw himself into coffee cold turkey too!
Going back on coffee is not the answer, though, as it leads to the same cycle of pain eventually. Best to stay away from caffeinated drinks altogether, including painkillers like Solpadeine that contain caffeine. Caffeine is bad news for headache and migraine sufferers. Even if it appears to cure a headache, which it can do, it's only because the body is getting a drug fix. The underlying issue is still there as long as the headache sufferer continues to drink/eat caffeine.
If your husband has stayed off Solpadeine and coffee since June, that is brilliant.
If he hasn't, the least painful way to withdraw is to do so very slowly, e.g. cutting down by a quarter of a tablet a day (or even a little less) and taking Solpadeine at regular times (e.g. 9AM, 1PM, 5PM, 9PM) to keep caffeine and codeine levels relatively stable in the blood. The sudden dips trigger the pain.
It might be too much to tackle Solpadeine and coffee all at once. Quitting Solpadeine is the more important task, then quitting coffee (slowly - check out www.teeccino.com for an easy, pain-free way to quit coffee).
I hope that helps…?
All the best,
Storm