Just that those things have no relation to each other. Coal is used to replace gas, not nuclear plants. And AFAIK in mid of April there is no winter any more anyway.
The question is valid, as there is a huge amount of misinformation going around those topics.
Nuclear plants in Germany only deliver electricity, and only where the grid is connected. But coal is used also used for heat and chemical processes, and outside the grid. No source of electricity can cover that yet in a short timeframe. And even if we are just talking about electricity in grid-connected locations, with the high cost of nuclear plants, it makes more sense to just buy it from others, and wait until new renewables sources were added to the grid, and long term build other replacements for heat and the chemical processes.
isn’t coal more expensive if you take all the negative externalities into account? Specifically increased rates of cancer and other diseases caused by pollution on top of CO2 emission?
Maybe, but that's irrelevant today, the original plans were crushed by reality, and now we must accept the mess and move on. Germany could have been in a better situation, if politicians did a better job a decade or two ago. But complaining today about the mess from yesterday, because of the fails from 12 years ago is pointless.
All that most Germans want to do, is to drive in their SUVs and park everywhere. That is what they vote for. Meanwhile they vote against nuclear (I'm scared) and wind (Verschanden meine Landschaft)
The question is valid, as there is a huge amount of misinformation going around those topics.