Perhaps, while the new baby is sleeping, you can play or read with the other child. Give them your undivided attention, so they will feel loved and secure. It is a must to set aside individual time for each child on a regular basis. Children need to hear what they do well. Be sure to praise your child for his or her uniqueness, strengths, accomplishments, and efforts.
Older children can be down right mean and sometimes torment younger siblings.
Parents need to intervene if it begins to get out of control. Blaming each other or tattling should be discouraged, letting them sort out some of their own problems by remaining neutral. If one is being bullied or harsh words are being said, disciplinary intervention may need to occur before things get out of hand. Then calmly discuss the situation. These are the times when you will need wisdom and patience to determine how best to seek justice for all injured parties.