How do I realize communication between child and parent component via click?

I have two components. The parent component contains a button, if I click on the button child it will be disabled and the child component opens and contains the button close. When can I close the child component and enabled the button in the parent component?

My Code:

// Parent
<app-child (currentChild)="setCurrentChild($event)" *ngIf="showChild"></app-child>
 <button type="button" (click)="openChild()" [disabled]="isDisabled">Child</button>

public showChild = false;
public isDisabled = false;

openChild() {
this.showChild = true;
this.isDisabled = true;
}
// Child
<button class="btn-close" mat-button (click)="closeChild()">close</button>

 @Output() public currentChild: EventEmitter<any> = new EventEmitter<any>();

closeChild() {
this.showChild = false;
this.isDisabled = false;
}

Source: Angular Questions