JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css">
<input type="text" id="dp"/>

JavaScript

var now = new Date();
var day = now.getDay();
var disabled = (day===5)? new Date(now.getFullYear(), now.getMonth(), now.getDate()+3): null;

$('#dp').datepicker({
    beforeShowDay:function(current){
        if (disabled !== null && disabled.getTime() === current.getTime() ) {
            return [false];
        } else {
            return [true];
        }
        
    }
});