Thanks everyone for the kind messages, I have an update:
I spoke to Andy on the telephone and he says that his father has improved quite a lot. He was breathing (although very laboured) and even managed to say a few words although he struggles to breathe if he tries to speak so they've told him not to speak.
The doctors plan is to put him on ventilation during the night and have him breathing on his own on 100% oxygen during the day, so that is what they are doing now.
We still don't know if he's going to pull through this but the fact he was talking is a major good sign.
Andy says the whole fiasco started a few weeks ago when his dad fell through a glass door (he's disabled and lost his balance) and he attained some nasty cuts to his head and legs. He recovered from this okay but then some ulcers developed on his leg where he had been cut and it made walking painful, so he just sat there in the house on his own and let it fester.
Because his immune system was down, the infection went to his chest and then developed into full blown pneumonia.
The poor man! If he recovers from this, I think he should get a home-help or someone to keep an eye on him as he's on his own, quite badly disabled (worse than me) and getting into his 60's. He's so staunchly independent, I don't think he would, though.
My own update: 18 days over, no bleeding, some pain when walking long distances, but no other symptom. I am starting to wonder what these dr's are talking about. Got my prescription for the pills but haven't taken any.
