I hope the antibiotic and other meds your Dad was given have some positive effect and that everything turns out ok. I know the waiting is an indescribably difficult thing to endure. Until you know for sure, you have to keep switching from those negative thoughts to all the possibilities there are for a positive outcome. Anything you can do to keep busy with other things helps - like going outside, exercise, working, - anything that takes your concentration away some of the stress. I'm sure others will have suggestions or experiences that more closely resembles your Dad's experience, so try to think about all the good things that could happen and do come back here often to let us know what is happening with you and your Dad.