Sick people all around. After treatment.

My in-laws remains sick all time... My baby got pneumonia and infection when he was newborn from cough and cold given by great-grandmother.. other five members remain busy in buffaloes and dnt take bath daily.. Directly pick and kiss baby ..when clothes are dirty and with too much smell.. They are totally uneducated and illiterate.. When I try to teach something they think I dnt want my baby to build love and affection for them.. my father in law has asthma too.. I m helpless my baby is formula fed from birth.. Now he is 4 month old.. I think he has very little immunity.. He is having mucus in throat and snoring all time nose remains blocked.. Cough is there.. He don't get well due to his family... Always try to snatch my baby ...another family member has whooping cough also.. Although I have vaccinated my baby properly with painless vaccination ...can he get pneumonia or whooping cough again after treatment... Is there any danger to his life