When a child is unable to cooperate and be flexible moving thru their day, the first thing I suggest is establishing a closer connection with him. Children thrive on connection with their parents and caregivers. Your son's need for a sense of connection will remain strong and constant through his childhood. This sense of safety and connection allow children to learn at a great rate, to experiment and play fully, to enjoy themselves and others without reservation, and to trust in the goodness of the people they know. This is also what makes a child able to be easy-going and to move through the transitions of the day with confidence.
You'll want to begin by starting a daily Special Time with your son, ideally for at least ten minutes every day before he goes to school. Often, Special Time encourages a child to try to express feelings that they need to offload. This reduces stress and helps the child build flexibility and resilience.
These articles will help you get more ideas to ease your son's transitions and help him respond cooperatively with his caregivers.
Let us know how it's going,
Hand in Hand Parenting