My guess is that your son has regressed. Young children will regress when they feel stressed. I think your son is feeling slighted by the attention the baby is getting. Now he’s being babyish so you’ll fuss with him like a baby.
It may seem to you that your son receives plenty of attention, but try to see life through his eyes. He was the baby of the family and once received a lot of attention. Now he has been displaced.
Here are some ideas that will help.
Plan some private one-on-one time with your 4-year-old each week. Even 20 minutes can make him feel important.
Make sure your son’s bedtime is later than the baby’s so he can feel more grown up.
Give him grown-up tasks to do to help around the house so he can appreciate his status in the family.
I have found that scolding, punishing and yelling at a child for soiling do not work. You’re just going to have to be patient as you help him understand that he doesn’t have to be a baby to get a lot of attention.
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.