How can I spectate someone else in a demo?

I feel kind of sketchy about one of the players in the server I play and I recently recorded a demo of him in action. Is there anyway to see the demo from his point of view?

I’m not sure if there’s a way to run Lua code whilst a demo is running, but if you can then technically you could

If you have ULX installed you can bring it up and use a command to force yourself to spectate another person in the demo, I believe.