Is it permissible for the children to use their deceased father's car, and what is the ruling on the money spent on its maintenance before the distribution of the inheritance, and is the testimony of witnesses sufficient to prove the deceased father's ownership of the car if the son claims it was a gift to him before the father's death?

If the car is part of the deceased's inheritance, it is owned in common by all heirs, and none of them may possess it exclusively. As for a father bearing witness to giving ownership of a car to his son: if the son is a minor who has not reached puberty, the father takes possession on his behalf, and the gift is considered effective, and the lack of official transfer of ownership does not harm its validity. Jurists have unanimously agreed on the validity of a father's gift to his young son who is under his care. If the son is an adult and took possession of the car and used it, the gift is valid even if its ownership was not officially transferred. However, if he did not take possession of it, the gift is void, and the car becomes the property of all heirs. The specialization of one son with a gift is a matter of dispute, but according to the Hanbali school of thought, if the father dies before reclaiming the gift, it becomes definitively established for the donee.