Sources close to Chris tell TMZ ... he set up a college fund for 9-year-old, Isis, and her education is pretty much covered. We're told he was solely focused on being a great dad, and it forced him to be very smart with money and investments.

Friends think that also made him a pretty hilarious penny-pincher, who rarely picked up big tabs or splurged on luxury items for himself. We're told Chris' inner circle wants to make sure Isis' college fund is managed properly, so his dreams for her will be fulfilled.

As we reported, Chris knew his family history of heart problems ... another reason he was determined to leave Isis enough to live comfortably.