Funnel chest is called, medically, pectus excavatum. It involves a condition in which the sternum (breast bone) is sunken into the chest.
The exact cause of funnel chest is not always known, although many cases are probably genetic (many people with funnel chest have relatives with the condition).
Usually funnel chest is an isolated condition that does not represent an underlying medical disorder. Therefore repairing it with surgery
can be done for two reasons. The first, and most common, is for cosmetic reasons. The second is that, in very severe cases of funnel chest, there is some concern that as the person grows the funnel chest depression
will push on the lungs and the heart and make them work less well. This is often looked for prior to surgery with special lung and heart function tests.
A certain number of cases of funnel chest are associated with an underlying connective tissue disorder, such as Marfan's disease. Children with funnel chest should be carefully examined by their pediatricians to make sure they do not have any signs of Marfan's disease or other connective tissue disorders.
If your family has further questions about this condition, talk to your brother's pediatrician