Colin's best friends

Harrison goes to school with Colin, and they spend a lot of time together. We have done some playdates at Harrison's and vise versa. A couple of nights ago, Colin accidently called Nathan "Harrison", and he thought it was so funny! So he kept on doing it! Last night Colin kept saying to Nathan, "Harrison, come over here." So I asked Colin, "Who is your best friend?" His immediate response, "Harrison and Nathan!" My heart just melted, Nathan is not only Colin's little brother but his best friend!