How can I help a family member whose spending is out of control?

I know someone in my family who is in big trouble with money. I tried to help him, asking him who he owes money to, but I think he is lying all the time. Lying to himself and to his family. I think he needs help but I don’t know who I should contact to help him. Maybe the underworld is blackmailing him? A women who he had something with is putting the squeeze on him? Maybe drugs? Gambling? Maybe hookers? I do not know what to think, but it seems very complicated and he keeps lying to get more and more money to pay his debt. I thought he might need to involve a psychologist to talk with him, but do not know if it can help. What to do?