He works in a restaurant and takes tips with the knowledge of the owner

Praise be to Allah.

We have previously discussed the ruling on accepting tips and “baksheesh” in the answer to question no. 82497. 

But if the tips in this case are given with the knowledge of the tour company for whom the driver is working, there is nothing wrong with that, because the restaurant can give some of the money to the company, so if it agrees to give it to the worker, there is nothing wrong with that. 

The same may be said with regard to what your father receives: if it is with the knowledge of the owner of the restaurant, there is nothing wrong with it, because the customer has the right to pay more than the agreed price, and if the owner of the restaurant agrees to leave this additional money for the worker, there is nothing wrong with that. But the worker or employee has to do his job properly and give the customer his rights in full, whether he gives him a tip or not. 

Shaykh Ibn Jibreen (may Allah have mercy on him) was asked: I work for a transportation company and I transport refrigerated fruit and vegetables from Madeenah to Jeddah or Makkah or Riyadh. When I arrive, the one to whom I am making the delivery gives me some money, 100 or 200 riyals, in appreciation for my delivering the vegetables to him quickly. Please note that the owner of the company knows about that. 

My question is: is this money or tip, as they call it, halaal or haraam? Please advise me, may Allah reward you with good. 

He replied: We think that there is nothing wrong with you taking the money that the owner of the grocery store gives to you when the owner of the company is aware of that, and the aim behind that is to encourage you to deliver the goods and take care of the vegetables before they go rotten. As you deserve it because of your effort and you taking care of the goods, and as it was given to you willingly by the owner, there is no reason why you should not take it, even if it is in addition to the salary for which you work. The aim behind it is to encourage you to carry on and to do what is in their interests. And Allah is the source of strength. 

End quote from Fataawa Islamiyyah, 4/347 

And Allah knows best.