Research has shown that a resilient brain is one that recovers more quickly from an upsetting experience. And you can help your children develop these brain signals and pathways when
they are young by building their Disappointment Muscles not only allowing them to experience their feelings so they can learn they are capable of dealing with negative emotion but also letting them recover from that experience to give them a sense of capability.
How to Address It?
The best way to start is to practice validating their feelings of disappointment without rescuing them or fixing the problem. The part you're going to work on is validating feelings. But the hardest part is not rescuing and fixing. The corollary here is that you must have faith that the child can survive the disappointment (trust me, he can).
Your Script in Action
Child: "I don't want to put my phone downstairs. We don't even get to go to school; at least I should be able to talk with my friends. It's not fair."
Parent: "I can see that you are very angry that you can't have your phone."
Bite your tongue...hard as it is.
Don't Rescue or Fix
Parent (if you feel you have to talk): “Why don't you take five minutes to finish up with your friends and then just take the phone down to the kitchen."
GOT A MINUTE?
Look for easy opportunities to validate and let them sit with it. Complaining about doing chores, the awfulness of online school, wanting to be outside instead of sitting at computer, not getting the grade he wanted. The message your child will receive is: I trust that you can handle the situation, the emotion, the disappointment; I believe in you.