No. Without a "moral law" there is no such thing as benevolence. Essentially, the question is "under a system where there's no such thing as benevolence, can a person be benevolent?"
And people confuse this with a moral society or a moral religion, which isn't the basis of the question. The question, boiled down, is if a person needs morals to be benevolent, which they do, because everyone has morals regardless of any other external factors. I read too deeply into these stupid things.
Are we talking about moral law or utilitarian law? Morals are just a set of codes, benevolent OR NOT, that a person lives by. Morals for me do not necessarily = what's best for anyone else. That's a dream we'd all love to have happen consistently.