He can but was it bought outright? Also do you know if his contract with Rogers ended the 3 years on it? seeing as the iPhone 4 8GB was released in Oct 14th 2011 as well i really doubt he finished the 3 years but ask him if he bought it outright.
If he bought it with a contact the ONLY way for him to get the unlock code is ask Rogers many times but really doubt that would work. Here are the policies for the unlock code from Rogers:
1.No contract on phone remaining 2.your account is in good standing ( seeing as its your uncles i really hope its in a Good standing.) 3.phone is in your device history (if you bought it from them it already is)
If all this is fine, then Rogers will give him the unlock code BUT he needs the devices in order to do this seeing as they give him instructions on how to do it.