Sanders doesn't have any control over it. They can spend it for him. It's called superpacs. It's called billionaires like Bloomberg or Steyer who decide to run anti-Trump ads. Technically he has no control over it, but he'll benefit from it nonetheless.Well...we'll see if that changes if he becomes the nominee. "Senator Sanders, if you are the nominee, do you want me to NOT use my money and resources to help you defeat President Trump?" Either he stays on message that billionaire money is inherently evil and that he would rather go into battle significantly outgunned on the money front than have help from those who have big money to use in the battle. Either he would know that Bloomberg probably despises Trump enough that he'd spend much money on Bernie's behalf anyway even if Bernie didn't want it, or Bernie would probably believe that he can beat Trump handily enough without Bloomberg's money. He would be telling Democratic voters whose top priority is beating Trump that he would turn down a billion dollars to that goal.
I get Bernie's position. I just don't think his consistent positions and issues are not most of the positions and issues of the Democratic party as a whole per se, his forever war is not with Trump, but a class war against the wealthy. Everything else is in service of fighting that war and the fight is the point, not the victory and viewed through that filter. That has been his consistent message and position ...always. Having effective weapons that were made by those who make weapons to fight against those who make weapons would be unacceptable. Better to go into battle with slingshots. The fight is what matters.
Sadly IMO...It is just not where most Democrats and independents are at. To them beating Trump is job one, and they realize it takes resources to do that, not purity that would have you turn down the resources because it came from someone who had it to give.