They were talking about how the candidates get to keep what’s in their till
No, it is not his money. It belongs to his campaign committee. It is not for personal use.
For an election run, a campaign committee must be registered with the Federal Election Commission (FEC). In this case it’s Ron Desantis for President.
Spending and income must be reported to the FEC, and the records are public. Spending is allowed for campaign activities, donating to other campaigns, and for charity.
Personal use is illegal, and you have seen news stories of candidates charged criminally for using campaign funds for their homes, cars, vacations, etc.
The committee will exist as long as it has money (or debt). To deactivate the committee they must spend any surplus or pay any debts. Committees can live on for years after their races are over.
I handle finances for a friend’s small local campaign. He’s not running again, but we have a little money still and I file quarterly reports with the state.