Is there any sin on him if he takes out a loan for someone else and he does not pay it off?

What we
understand from your question is that you want to take out a loan in your
name, so that someone else may benefit from it, and this person may or may
not pay it off. In that case you will be expected, according to sharee’ah,
to pay off the loan because apparently you took it for yourself, and the
loan was given on that basis. 

If you know
that the borrower will never pay it off, then you should not help him to get
that loan, because by doing that he is a wrongdoer and aggressor who is
exposing himself to the punishment mentioned in the words of the Prophet
(peace and blessings of Allaah be upon him): “Whoever takes people’s
wealth intending to pay it back, Allaah will enable him to pay it back, and
whoever takes it intending to destroy it, Allaah will destroy him.” Narrated
by al-Bukhaari (2387). 

But if you
intend to pay it off for him if he refuses to pay it off, then there is
nothing wrong with that, and you will have done him a favour with this
money.  

To sum up:
So long as the loan is in your name, then according to sharee’ah you are
responsible for paying it off. 

And Allaah
knows best.