OK, everyone needs to stall the digger for a minute.
The Form 11S is a new form for 2011 et seq. Everyone appears to be assuming that the OP's friend's employer in the restaurant has given this form to them. This isn't possible, as they are not generally available - Revenue issue them directly to the taxpayers whom they want to return them.
Taken from Revenue Operational Manual part 38.01.12:
"The Form 11S is a new form. This is the shortest and simplest of the Income Tax return forms. It will be sent to a targeted audience of compliant taxpayers whose affairs are not overly complex and who have income below a certain threshold. It will also be sent to non-compliant taxpayers whose tax records do not indicate that the large Form 11E would be more suitable. There will be no printed stock version of this form, nor will the form be available on the Revenue website – see 2 below"
...
"2.1.Requests for the Form 11S
As mentioned above, this form will be sent to those customers to whom it is deemed appropriate; as it is a very shortened form it is not suitable for customers whose affairs require a more detailed tax return.
As it has a targeted audience, there will be no blank stock of this form available, nor will the form be made available on the Revenue website."
So, this person's employer may or may not have them on the books properly, we can't know either way, but it's pretty clear the issuing of the Form 11S is unrelated.