If he's not in a position to sell his car, of course it's worth a shot. It is my understanding that the engine coolant also cools the cvt fluid, so if the coolant is low or bad, a flush would help to keep the fluid cooler. As for cvt flush, if you read my backlog I was having the same issues with a noisy cvt. Turns out I had a slow leak from a bad fill tube seal which dropped the cvt level and burnt out remaining fluid. I dropped the transmission pan myself and drained and filled my cvt and I have not had a problem since.Dodge highly discourages any but the radiator flush on these cars. A TSB was even released to prevent dealers from doing flushes. The radiator flush will do nothing to fix the issue, anyways. Everyone that has had this issue have had to replace the CVT in the end. Your advice is unsound based on the history of this issue.
So my advise is based on my personal experience with my cvt. sharing my advice based on personal experience with someone to help them save their car instead of throwing their hands up in the air and just trading it in shouldn't be shut down so readily.