Law frim won 2.5 mill &night car with 500;000 cash. Scam from 2012 still running.

My father (age 83)  is being scammed by these people. So far he has sent them $50,000 and still believes he is going to get the $18 million dollars, 2 cars and a house in Florida. They call him at all hours and the day I learned about this the man on the phone was yelling and screaming at my dad that the needed $30,000 more to process his winnings. I showed my
father Larry's post and tried to show him it's a scam. This morning (Sunday) they phoned my father at 5:30 am demanding
that he fly to Florida to see the new house he won. How do I stop these people?????    

You probably can't.  You will need to take control of your father's finances, change his number and hope he doesn't call them and give it to them.  I would suggest you file a police report, contact your State Attorney General's office, as well as the local agency on the aging for assistance.  We have seen this story many times before, and they will bleed him dry until he has no money left.  You are going to have to interfere no matter what in this matter.  Unfortunately sometimes people at that age are not able to fully comprehend what they are doing or not able to make the correct decisions based on what they have learned over life.  This is a sad fact, but something that you must face and you must face it immediately.  i will ask that some of the other regulars post a reply to your situation along with some other agencies that you can contact for help.

BigA covered your question well.  Could you become power of attorney for your dad?  Is there any way you could monitor the calls (turn off the phone/ringer if you are not available, etc).  The thief will continue to call as long as he believes your dad will pay - sorry to say there are people like that in the world!  Could you ask a very trusted friend of your dad's to talk to him about this scam?  He might believe them before he believes you (sad to say!).

Could you have a financial institution handle his financial affairs??  We did that with my elderly parents.

BigA and MJG offered good advice.
Are you on good terms with your father?  If not, is there another, trustworthy, family member who is on good terms?
Does your father have reasonable mental facilities?
If your answer is "yes", consider changing his existing accounts to (your father) AND (trustworthy person).  That means checks would require both signatures.  (If the transfers are via card, call the issuing agency and put a low limit on the card).

If your father's mental capacity is  slipping, then consider BigA's and MJG's suggestions.  Remove his easy access to his finances.  You could keep them in his name, but change the ownership to (your father) OR (trustworthy person).  See the difference?  If his mental competency is in doubt, consider removing his access entirely ... place the funds in a trust account or other account to which he does not have access.  (See a lawyer ... there may be tax impacts).

Of course, you would need your father's cooperation in two of the above three cases.

Also, strongly consider attaching a call blocker to his phone ... one that you could program to stop calls from any suspicious number.