Irving Fein was the longtime personal manager for Jack Benny and George Burns. When one of your clients lives to be 100, it's not easy to outlive them but Irving did. He died a few days ago at the age of 101.
If you're interested in either of his clients (but mainly Benny), do yourself a favor and track down the book he wrote in 1977 entitled Jack Benny: An Intimate Biography. It's a good bio but a lot of it could be subtitled, "What it was like to be Jack's manager." He has some pretty interesting stories in there about repping Benny and handling his business dealings.
Here's an obit for Mr. Fein.