Answer:
He should stay at home to take care of his baby brother.
Step-by-step explanation:
Robert should not go downtown to hang out with his friends because of the following;
=> Robert should be obedient: Robert should be obedient to his mum since Robert's mum asked him to stay with his baby brother, he should do just that.
=> Taking the baby out to hangout with his friend or leaving the baby behind might poses great danger or harm to his baby brother: ones family comes first, the protection or safety of his baby brother should come first before thinking about pleasure. Even if the baby is not his brother the first thing is safety and protection for the baby before pleasure. That is the reason we are humans.