How old is he? Do you want to change his name to give him a fresh start or do you no want a different name so people don't associate him with you?
Name changes are not all that difficult I believe but I think changing a name to avoid legal consequences is a disqualifier.
My daughter changed her name by deed pole. I was told that it was her way of separating her life in two parts. She could use either name depending upon her motive. It was not a positive thing to do. It almost convinced her she could behave in any way and have no consequences. She changed it back again following another reunion with me. Although I know she continues to use both names especially at work. She wants to keep her job and feels she can separate this part of her life from any chaos / trouble that she causes.