abuse to turtle

Question
my freind has a red slider [wich i think is illegal in cali]last i went to his place i notised there was no UVB light all i saw was the heat lamp i asked if it was a vapor mecury bulb and he looked at me all confused. i later realiized he had no clue wat UVB  was i told him about mbd and he sed that he has had his turtle for 3 years and has had no problums there for i was wrong. is there by any chance  this turtle does not need UVB? if not can u tell me wat to do to convince him to buy a UVB light

Answer
 I have made it pretty clear on my profile that I answer questions about lizards and lizards only.
 What I do have, as an expert and informative answer is a section from what most reptile experts and exotics specialists consider the most informative on most reptiles, including turtles:

http://www.anapsid.org/reslider.html

The article specifies red ear sliders.  This should prove to your friend the importance of UVB for his turtle.  Many reptiles can exist without UVB for a long time and not show symptoms, but if he's been without UVB for 3 years, he's not a happy turtle.