I have chatted with Davo about his illness occasionally via PM. Although I think it's been a few months since the last message.
I don't have a lot of detail but it's not good news I'm afraid. I can only hope and pray that this is just a short term blip while he's having treatment and he will return at some point. But I fear the worst.
As far as I know the cancer is not curable and any treatable is likely to be palliative.
I believe that the depressing reality is he will continue to deteriorate and it's just a matter of time. The timescales are probably not going to be years. Fortunately he has a good family support network.