Could be more tricky then we know. If he did indeed commission said artist about it, then it's certainly a possibility that he requested the artist to work around his own artistic vision for it, i.e. "make it with two hands reaching for each other... position it this way. " etc. It really depends on the terms of service that the artist provided to hill. Hill could have commissioned him to create it, whilst paying him enough to own the original image as well; allowing him to modify it to his own desire .
Otherwise its just a concerned homie looking out for a friend, but ya know... not having the full story. Not a good idea. This could be detrimental to both parties involved with in itself, reputation-ally speaking. Because the third party getting himself involved may not be privy to the details of communication, John hill could come out looking shitty for it, and the artist may also lose potential clients who wouldn't want to deal with any potential friction when working with him.