See this post: Hide weekend in calendar SharePoint 2013
end result from one of the comments in the related post:
script used:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script><script type="text/javascript">
$(document).ready(function(){
var oTable = document.getElementsByTagName("table");
if (oTable != null) {
for (i = 0; i < oTable.length; i++)
{
var table = oTable.item(i);
if (table.className == "ms-acal-month")
{
for (var c = 0; c < table.rows.length; c++)
{
if (table.rows[c].cells.length == 8)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
table.rows[c].cells[7].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 7)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[6].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 6)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[5].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 2)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
}
}
}
}
}
});
function month(){
var oTable = document.getElementsByTagName("table");
if (oTable != null) {
for (i = 0; i < oTable.length; i++)
{
var table = oTable.item(i);
if (table.className == "ms-acal-month")
{
for (var c = 0; c < table.rows.length; c++)
{
if (table.rows[c].cells.length == 8)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
table.rows[c].cells[7].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 7)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[6].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 6)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[5].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 2)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
}
}
}
}
}
}
//For week view
function week(){
var oTable = document.getElementsByTagName("table");
if (oTable != null) {
for (i = 0; i < oTable.length; i++)
{
var table = oTable.item(i);
if (table.className == "ms-acal-detail")
{
for (var c = 0; c < table.rows.length; c++)
{
if (table.rows[c].cells.length == 8)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
table.rows[c].cells[7].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 7)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[6].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 6)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[5].style.visibility = "hidden";
}
else if (table.rows[c].cells.length == 2)
{
table.rows[c].cells[0].style.visibility = "hidden";
table.rows[c].cells[1].style.visibility = "hidden";
}
}
}
}
}
}
$( "#WPQ2_nav_prev_a" ).click(function() {
month();
})
$( ".ms-picker-table" ).click(function() {
month();
})
$( "#WPQ2_nav_next_a" ).click(function() {
month();
})
setInterval(function () { month()}, -10000);
setInterval(function () { month()}, -10000);
setInterval(function () { week()}, -10000);
</script>
the weekend columns are just blank for the view, they don't actually disappear from the list as they are needed for the calendar to technically functionality to actually work.
An Outlook alternative for this would be to have them import the calendar to Outlook and use the "work week" button in the ribbon to do the same thing.