What should a man do who ran over a person with his car ten years ago, causing their death, then fled out of fear of the deceased's family, and now his conscience troubles him and he fears facing them?

This man must declare the truth to the deceased's guardians; his repentance and commitment are not complete except by fulfilling the rights or being forgiven for them. If what happened was an accident, then the blood money (diyah) is due from his 'aqilah (male relatives on his father's side), and he must expiate by freeing a believing slave; if he cannot find one, then by fasting for two consecutive months, along with repentance. Allah Almighty says: "And whoever kills a believer by mistake - then [the penalty is] the freeing of a believing slave and a compensation payment presented to his family [from his aqilah] unless they give [it up as] charity." (Quran 4:92) However, if he killed him intentionally, then qisas (retribution in kind) applies, life for life, unless the blood guardians pardon or accept blood money from his personal wealth.