Damn, sounds like a rough road. 
My dad decided against Warfarin but it sounds like your dad has a more severe case. A cardiologist suggested an ablation procedure to my pop, where they sever a nerve which is misfiring and causing the fibrillation. If your dad's fibrillation is constant and the Warfarin is bad news, it might be worth asking about.
My dad's is intermittent, couple times a week for varying durations. But like I said, when he was on antibiotics there was no fibrillation at all for weeks on end. (It was a particular sort of antibiotic that could treat a prostate infection. I think the 3 'privileged' organs are the prostate, heart, and brain, and require special drugs which can get in there.) Perhaps there could be a connection between your dad's pneumonia and his AF?
Did your dad ever have a urinary tract infection? That was how this all started for my dad. Or do you remember an infection or illness of any kind as the beginning of his fibrillation?
Man, you're scaring me.
I know he had prostate issues, he sorted that out. Then the atrial fibrillation just long enough after the prostate stuff to make a connection nebulous. Two stents in his heart after angina showed up, no ongoing heart troubles other than the fibrillation. He got urinary tract infections after the pneumonia (which masqueraded as a common cold for a couple of days until he started going blue). The delirium that came with the urinary infections was NOT fun. He didnt even know who I was. Couple of courses of antibiotics and he was fine. But he does get them more often.
Take home message, look after yourself, catch the weird shite early and pray like hell the heavy stuff skipped your genes and that docs never get their claws in you.
I'll look into the ablation op, thanks. The thing with warfarin is how good its statistics are. Way lower prognosis for stroke, but they get fragile really fast.
He fell in the shower last year and I had a devil of a time lifting him. You cant grip hard cos he'll bleed under the skin, cant drag him. I threw a towel over bits a daughter should never see and luckily he had just enough strength to grip me around the neck in a hug. So I lifted him up from a squat and got him out where he slid down onto a chair I put right outside the shower. He's 96kgs, so it wasnt fun.
Hope your Dad weathers this stuff better.
Reckon BIG ACH is going to see a doctor?
