If he's in prison for life without the chance of parole, why does it matter to him if his debt is paid off?
Prisoners work jobs that are exempt from minimum wage and can pay as little as 25¢/hour.
Having your wages garnished while in prison is a huge deal because it limits your ability to take care of yourself (both literally, but also your ability to trade items with others for protection).
If you don't have access to money in prison, you're screwed. Unless you have some other valuable asset (such as connections on the outside that you can leverage), you are likely to be a target for other inmates, and you're going to be a filthy, starving wreck.
The exact details vary depending on the type of prison, the location, and other factors, but in general: having the debt wiped out would almost certainly be a huge deal for his quality of life in prison, and would literally extend his expected lifespan.
[0] https://www.washingtonpost.com/opinions/2022/03/25/prison-pe...
Garnishing prison wages is fucking brutal and stupid though. Prison laborers typically make less than a quarter per hour, so that isn't going to do shit in terms of repaying any debts, it's just a spite play to make someone's life miserable.
Honestly, if I was Ross I'd refuse to leave my cell and act insane till I got placed in solitary. In most prisons you can still have books in solitary, you just lose out on yard and TV access, which is still a great trade if you're getting regularly beaten and hate raped.
You're describing the idealized scenario, which isn't exactly wrong, but it doesn't represent the reality that many prisoners actually live in. Yes, it varies - not every prisoner will have the same experience, even within the same prison - but having access to basic necessities is by no means a given in prison, and having wages garnished makes that much harder.