Neither should be fighting imo. Both are old AF! Sad seeing old past it fighters still fighting.
It's fine as long as the organizer uses a proper safety measurement, like x rounds, x minutes, and x pounds gloves, etc. It's similar to football legend exhibition matches. Well, some of the legends still competitive despite their age. See how Scholes and Beckham played.
https://www.youtube.com/watch?v=0vbfI99IsAY