You are definitely worrying for your child's attitude . that's normal.., but dont be too paranoid that he will get that attitude of your sister in law..uhmm.. all you can do is you should spent some time with your son,. and preach him or talk to him .. about the good traits, right manners, and attitude .. so that he will apply it to himself.. GOOD BONDING OF MOTHER AND SIBLINGS can be the foundation of the siblings..
kurdi