Nile monitor (very mad at how he was treated)

[Odynxjules]

Ok, so here's the story, my ex-roomate bought a nile monitor a year ago and never cleaned out his cage......once....except when he moved him to a new one. And never handled him because he wanted ot keep him "on a primal lvl" because thats what he connected with, now I am assuming responsiblity for it for alteast the next 2 years in hopes to make him handle able enough for an actual expert. His name is Odyn, rightfully named I think. But I was wondering if there was anyone out there that could help me with something. He hasn't eaten in the last couple of days because I have been busy in the morning forking and we haven't had frozen rats. and for the most part that is what he has been fed on since he has gotten big enough. If I were to feed him live would that make it so he can't eat frozen again, or would I be able to switch him back when necessary? And if I were to switch him around with food, what would be a good recomendation. I think he was about.....a few weeks old when he got him?