assalamu aleykom ustadh, My father is a taxi driver, he takes every ride, including restaurants. Big chance they will drink alcohol. From my knowledge the money he receives for those rides is not halal. However he askes me sometimes to do the bookkeeping of his company. Am I allowed?

Ustadh AbdulAziz al-Haqqan

It is not sure that they will drink, so we can not jump to the conclusion that it is forbidden. Also he is taking them to a restaurant and he does not know for sure what they will order so we can not base rulings on mere doubts.