U can advice ur frnd by saying if we keeps on making noise at class while teaching , it not only affects that child but the whole class.
also not listening in class makes us at a difficult stage at exam times.
if we listen in class we will be able to understand the concepts much clearly n also we will be able to write the answers in own during exam times.
it can help at our exam times
so it is very important not to make noise at class while teaching.
hope it can help u