Salaam. The person who connects me with people whom i sell and buy cars from happens to be a Fasiq, because he brings in different ladies into his room. Though i haven't seen him commit zina, but i am suspecting that he is commiting zina with those ladies. I once heard him say he hit someone with a car while he was travelling one day but didn't wait to see whether the person was badly injured or even dead. But he takes the obligatory prayers very seriously, he hardly misses congregation. Can i continue doing business with him, since that's the only thing that interacts us and the money is mine, he is just like an agent who connects me with buyers and sellers of cars. Will my money be halal?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.

What you mentioned about the man does not prohibit you from working with him. Commercial transactions are permissible with a non-believer, and with greater reason with a sinful Muslim. It is narrated in the two Sahihs (Al-Bukhari and Muslim) that ‘Aishah reported: “The Messenger of Allah, sallallaahu 'alayhi wa sallam, purchased food on credit from a Jew, and he gave him his shield as a pledge.”

However, it is advisable to, as much as possible, advise that man and remind him of the need to abstain from sins and to hasten to repent before he passes away while continuing in disobedience.

Allah knows best.