and if you put aside the fact that we are in Qatar and you need an NOC.
It is becoming standard in most companies world wide to include a 2 year local employment ban in some cases and depending on position in can be up to 10 years, given that they have a local employment ban in the contract,you will also find that somewhere in his contract or even in a separate contract there will also be a confidentiality agreement which will entail that he may not talk directly about any projects that the company is tendering/working on or about the company workings such as financial position, any engineering systems that the company specifically hold patent rights,copy rights or exclusive licensing rights,to persons outside of the company.

As Amoud said it's so they don't go and give away "Trade Secrets" to a competitor, the only Thing is that the ban will being place even after he completes his contract and does not take up the option of extending his employment with the company. Even in these contracts O/S the only way the ban can be voided (and something you want to tell your brother to make sure is stipulated in the contract) is if his contract is terminated through redundancy.

"Your born, You Live, You Die, given this premise, one can conclude since we have no control over when we are born and when we die, the only thing that matters to us should be how we live, simple really?" Mis-Cat to her philosophy Lecturer.