I have a roommate that has a box turtle. He's had it for years, and I've never paid any special attention to it. I am hardly at the apartment, as I pretty much live at my boyfriends house. Anyways, he is gone for 2 weeks and asked me to take care of the turtle. He tells me to change the water every few days, and to feed him every few days. Ok I say.

Well, I first went to check on him last monday after work, his water bowl was nasty. I cleaned and scrubbed it (it was green, and the bowl is pink) and gave the turtle fresh water, which he immediately dove in and pooed. Irk. Anyways, left him, bought some more food. T-rex box turtle food.

Today, chris and I go back to check on him, I notice when I pick him up that he poos, and his stool is runny and green. His repti-carpet is black where he lays. I decide to wash the carpet. I PEEL it off the glass, there is mold, old food, nasty stuff gluing this to the glass. I am so disgusted, I clean everything up, wash off the turtle, go and buy some repticarpet, and nail trimmers. This guys poor nails and beak! he has a severe over bite, and his back nails were so deformed and it looked painful. I did my best to trim the nails, changed the carpet, gave him fresh food and water. His shell is dry and deformed looking. I'm sure he doesnt have proper UV lighting, as it is on 24 hours a day, and probably old. His humidity is non existent. He has a heat rock, and a ceramic dish thing that barely holds food without it spilling all over the place.
I have been up since 3 am thinking about this animal that I now know is in horrid conditions and health. I got up at 3:30 to look at care sheets, and now it just makes me worry even more. My roommate has always loved turtles as a child, so this box turtle cant be that old.
What am I to do? Should I tell him how to correct his husbandry and hope he does it? Or should I offer to foster the turtle? I dont know how to go about telling him his set up is horrendous, and Im surprised the turtle is still alive. He is a great friend, and is even considering getting a corn snake. But after this, I will tell him a snake is just not plausible with how he doesnt care for a turtle properly. Any thoughts or suggestions are welcome.