Right-wingers are licking their chops right now. The only way they can pick up any Democratic seat in the country right now is through death or resignation.
I think Johnson will be fine.
Actually I would like to point out that 'strokes' are pretty easily faked by the medically competent.
I know if I had been a Democratic Senator in the current situation I would have been absolutely
terrified I would be assassinated in this fashion.
I have no doubt it will prove to be much better done than the radiation poisoning in London.