What Causes Swelling In Foot, Coughing And Getting Senseless?

Hi, I am from bangladesh. my father is diabetic patient & few week ago he is being suffering cough, when he coughing he is sensless. after couple of minute he is ok. another problem is his right foot is always swelling,in this condition what can i do? his age is 57 years, diabatis since more than 15 years.