Well, bless his honest heart! And it is reportable income although, because it is less than the $600 reporting threshold, he may not receive a Form 1099. If he is not in the business of writing copy, he could report it on Line 21 of Form 1040 as Other income but, because it is over $400, it is subject to Self Employment tax so he would also file Schedule SE. If he had any expenses related to this income, he may instead be better off with a Schedule C-EZ, not too complicated if the expenses are easy, and Schedule SE.
If he is truly not in this business, he may just report it on Line 21 and pay only income tax, not self-employment. As always, it depends and you will likely receive other suggestions, too.