Siblings of any age need reassurance that they will not lose love. They want their usual and essential activities with their parents.
Quality time and activities with each parent one on one help them know they are still loved and valued.
Siblings need Support To remember they are loved
When I come to the home where there is a sibling who is jealous, upset or showing signs of regression, I spend time with them and observe them with the baby and alone, also with mom and dad. Then I make recommendations to parents to help the child adjust. I help the parents make a plan that is realistic for the whole family.
Safety tip: Never leave a toddler alone with a newborn. They do not know what can be dangerous for babies and may act out feelings innocently in your absence.