He took a student loan and did not know that it is haraam

Question

Praise be to Allah.

What appears to
be the case from your question is that this loan was a riba-based loan.

If a Muslim
takes out a riba-based loan, not knowing of the prohibition on doing so,
there is no sin on him regarding what has passed of that. But after finding
out about the prohibition, he must put an end to any riba-based transactions
that he is currently engaged in, in whatever way he can, and he must refrain
from entering into any new transactions on that basis. He must also resolve
not to do that again in the future.

Allah, may He be
exalted, has declared the Muslim to be free of sin if he commits a sin by
way of error or because he was unaware of the ruling on it. Allah, may He be
exalted, says (interpretation of the meaning):

“And
there is no sin on you if you make a mistake therein, except in regard to
what your hearts deliberately intend. And Allah is Ever Oft-Forgiving, Most
Merciful”

[al-Ahzaab 33:5].

And Allah, may
He be exalted, says concerning those who consumed riba before it was
prohibited (interpretation of the meaning):

“So
whosoever receives an admonition from his Lord and stops consuming Riba
(usury) shall not be punished for the past”

[al-Baqarah
2:275].

As-Sa‘di (may
Allah have mercy on him) said in his Tafseer (p. 959):

Everyone who
repents from riba, if that has to do with transactions done in the past, may
keep what he previously acquired, but it remains to be seen (that is, in the
future – will he refrain from riba or go back to it?). But if the
transactions are currently in effect, he must only take back his capital; if
he takes anything more than that, then he has transgressed and engaged in
riba. End quote.

In other words,
whoever consumed riba before it was prohibited, there is no blame on him for
what happened in the past. The same applies to the one who deals in riba
when he is not aware of the prohibition on it.

This has been
explained previously in the answers to questions no. 2492
and 106610.

Based on that:

If your son
finds work that will give him the income required in order to pay off the
loan, then he must pay it off. If it is possible for him to pay off the
capital only, and have the interest waived, that is better for him, and the
body that gave the loan does not have the right to take from him more than
the original capital.

If he cannot pay
it off except with the interest, then there is no sin on him for paying it,
so long as he took the loan before he was aware of the prohibition.

But if your son
cannot find work that will enable him to pay off the loan, according to the
conditions stipulated by the body that gave the loan, then there is no blame
on him for that, and Allah does not burden any soul with more than it can
bear. And there is no blame on him if he waits until Allah, may He be
exalted, grants him some provision, at which time there is no blame on him
if he waits until he finds work that will give him the salary mentioned, so
that he will be able to pay off the riba-based loan and rid himself of it,
or the lender waives it for him altogether.

The lending body
only stipulated that condition so as to make it easier for the students who
took the loan; it was fully aware that some of them or most of them would
never have the opportunity mentioned, so it stipulated that condition,
promising to waive the debt if a borrower is unable to pay it off in the
manner stipulated.

For more
information, please see the answer to question no. 9700.

And Allah knows
best.