I'm no expert on the matter. But from what I know, Sinatra was a decent guy, with a big heart. He quietly supported a lot of his colleagues who had fallen on hard times, Lee J. Cobb being one of those.
But Sinatra was also an unsophisticated man. He had an admiration for the Mafia, much as an unsophisticated German might have had an admiration for the Nazis.
I never cared for him one bit, but he gets a big gold star in the charitability category.