how does boys show maturity beyond their age??

Nicola and jacopo works hard day and night.they sell newspapers,run errands,guide tourists,shine shoes and do much more.war had killed their widowed father and had thrown them into the streets.yet war had not broken their spirits,they bulid from what was left after the war,and returned only to find out that their sister was suffering from tuberculosis of spine,yet they didn't give up ,they brought their sis to the hospital and paid each weeks fee on time,by doing all this the boys showed maturity which was beyond their age