Under Qatar Labor law, you can file a "Termination of Contract" when there are grounds for termination. Not resignation but termination of contract.
Article (51)
The worker may terminate the service contract before its expiry. date if the contract is of a
definite duration and without giving reasons for the termination if the contract is of an
indefinite duration and retains his full right to obtain the end of service gratuity in the
following cases:
1. If the employer commits a breach of his obligations under the service contract or the
provisions of this law.
2. If the employer or his responsible manager commits a physical assault or immoral act
upon the worker or any of his family member.
3. If the employer or his representative has misled the worker at the time of entering into
the service contract as to the terms and conditions of the work.
4. If continuance with the work endangers the safety and health of the worker provided
that the employer is aware of the danger and does not take the necessary steps to
remove it.

The case of your friend falls under no. 3. Hope this helps.