Your child had an attack of upper respiratory tract
infection. This is the cause for the cough
at he same time your child had middle ear infection
which was responsible for rupture of the ear drum. Coughing cannot cause rupture of the eardrum
. But, one thing I need to know is, did your child complain of any earache? It is indeed difficult to have a perforation of the eardrum without earache. You should avoid water into child's ear, use saline nasal drops and give him only warm water for drinking. Get an ENT opinion also.
Dr. Naveen Kumar