What is the ruling on a young man who stole his father's car and drove it at a瘋狂 speed, leading to the death of five people, and is the punishment waived for him if this occurred in a country that does not rule by Islamic Sharia?

The act of the young man taking his father's car without his knowledge and driving it at an excessive speed, resulting in the death of five people, is a very grave error. This is considered accidental killing (qatl al-khata'), and the young man must offer expiation (kaffarah (definition)) for each life. His 'aqilah (male relatives on his father's side) are responsible for the blood money (diyat) of all the deceased, based on the Almighty's saying: "And whoever kills a believer by mistake, then [he must free] a believing slave and [pay] a compensation (diyah) delivered to his family, unless they remit it as charity." [An-Nisa: 92]. As for the unseen (batin) aspect, the young man may not be spared by Allah from the consequences of intentional killing due to his causation of it. However, he will not face qisas (retaliation in kind) as long as the killing was not intentional, and he may be subject to ta'zir (discretionary punishment) from the authorities.