Hi thanks for asking question. There are less chance of spread of organism in pleuricy case until your father having cough or secretions. Advise your father to take care that during sneezing, nose covered with handkerchief. Cough discarded in separate container. You should not come contact with any secretion of your father to prevent spread of organism through contagious. Mostly when your father will recovered from pneumonia within week ,then no chance of spread of it. In between also maintain your immunity to prevent infection by taking enough healthy nutritional diet. I hope you understand my concern. Thanks. Still any doubt ready to help you.