Colonel, C. S. Prov. Army, Comdg. Dept of Texas." Anderson escaped sometime before November 11, 1861.
"An act respecting alien enemies, approved August 8, 1861....
SEC. 3. Immediately after the passage of this act the President of the Confederate States shall by proclamation require all citizens of the United States, being males of fourteen years and upward, within the Confederate States and adhering to the Government of the United States and acknowledging the authority of the same, and not being citizens of the Confederate States nor within the proviso of the first section of this act, to depart from the Confederate States within forty days from the date of said proclamation and such persons remaining within the Confederate States after that time shall become liable to be treated as alien enemies; and in all cases of declared war as aforesaid aliens resident within the Confederate States who shall become liable as enemies as aforesaid, and who shall not be chargeable with actual hostility or other crime against the public safety, shall be allowed the time for the disposition of their effects and departure which may be stipulated by any treaty with such hostile nation or government; and when no such treaty may exist the President shall prescribe such time as may be consistent with the public safety and accord with the dictates of humanity and national hospitality."
Sounds like he was treated legally to me.