You can't keep covering up for your younger brother.
Tips
usage
包庇 always has a negative connotation — it implies protecting someone from deserved punishment. Compare with 保护 (bǎohù), which is neutral/positive 'to protect'.
grammar
Often used in the pattern 包庇 + person/criminal: 包庇嫌疑人 (shield a suspect), 包庇逃犯 (harbor a fugitive).