I once asked a christian who was protelizing, about someone who was a murderer , Had kidnapped someone and committed a gruesome crime (This was a national news story) if they would accept “Him” , the frankly admitted that was the christian way, but they themselves admitted it would be hard for them to accept it.
I really dont think Madoff could ever do enough tshuva for his crimes, besides stealing the money, it was a massive chilul hashem and he wasnt even religious